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uprobes/core: Clean up, refactor and improve the code
Make the uprobes code readable to me: - improve the Kconfig text so that a mere mortal gets some idea what CONFIG_UPROBES=y is really about - do trivial renames to standardize around the uprobes_*() namespace - clean up and simplify various code flow details - separate basic blocks of functionality - line break artifact and white space related removal - use standard local varible definition blocks - use vertical spacing to make things more readable - remove unnecessary volatile - restructure comment blocks to make them more uniform and more readable in general Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Anton Arapov <anton@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Link: http://lkml.kernel.org/n/tip-ewbwhb8o6navvllsauu7k07p@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar
+10
-4
@@ -66,13 +66,19 @@ config OPTPROBES
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depends on !PREEMPT
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config UPROBES
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bool "User-space probes (EXPERIMENTAL)"
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bool "Transparent user-space probes (EXPERIMENTAL)"
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depends on ARCH_SUPPORTS_UPROBES
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default n
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help
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Uprobes enables kernel subsystems to establish probepoints
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in user applications and execute handler functions when
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the probepoints are hit.
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Uprobes is the user-space counterpart to kprobes: they
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enable instrumentation applications (such as 'perf probe')
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to establish unintrusive probes in user-space binaries and
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libraries, by executing handler functions when the probes
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are hit by user-space applications.
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( These probes come in the form of single-byte breakpoints,
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managed by the kernel and kept transparent to the probed
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application. )
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If in doubt, say "N".
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@@ -1,7 +1,7 @@
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#ifndef _ASM_UPROBES_H
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#define _ASM_UPROBES_H
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/*
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* Userspace Probes (UProbes) for x86
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* User-space Probes (UProbes) for x86
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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@@ -24,19 +24,20 @@
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*/
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typedef u8 uprobe_opcode_t;
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#define MAX_UINSN_BYTES 16
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#define UPROBES_XOL_SLOT_BYTES 128 /* to keep it cache aligned */
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#define UPROBES_BKPT_INSN 0xcc
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#define UPROBES_BKPT_INSN_SIZE 1
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#define MAX_UINSN_BYTES 16
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#define UPROBES_XOL_SLOT_BYTES 128 /* to keep it cache aligned */
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#define UPROBES_BKPT_INSN 0xcc
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#define UPROBES_BKPT_INSN_SIZE 1
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struct uprobe_arch_info {
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u16 fixups;
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u16 fixups;
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#ifdef CONFIG_X86_64
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unsigned long rip_rela_target_address;
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unsigned long rip_rela_target_address;
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#endif
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};
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struct uprobe;
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extern int analyze_insn(struct mm_struct *mm, struct uprobe *uprobe);
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extern int arch_uprobes_analyze_insn(struct mm_struct *mm, struct uprobe *uprobe);
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#endif /* _ASM_UPROBES_H */
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+68
-61
@@ -1,5 +1,5 @@
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/*
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* Userspace Probes (UProbes) for x86
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* User-space Probes (UProbes) for x86
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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@@ -20,7 +20,6 @@
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* Srikar Dronamraju
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* Jim Keniston
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*/
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/ptrace.h>
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@@ -42,10 +41,10 @@
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#define UPROBES_FIX_RIP_CX 0x4000
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/* Adaptations for mhiramat x86 decoder v14. */
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#define OPCODE1(insn) ((insn)->opcode.bytes[0])
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#define OPCODE2(insn) ((insn)->opcode.bytes[1])
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#define OPCODE3(insn) ((insn)->opcode.bytes[2])
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#define MODRM_REG(insn) X86_MODRM_REG(insn->modrm.value)
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#define OPCODE1(insn) ((insn)->opcode.bytes[0])
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#define OPCODE2(insn) ((insn)->opcode.bytes[1])
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#define OPCODE3(insn) ((insn)->opcode.bytes[2])
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#define MODRM_REG(insn) X86_MODRM_REG(insn->modrm.value)
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#define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\
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(((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
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@@ -55,7 +54,7 @@
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<< (row % 32))
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#ifdef CONFIG_X86_64
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static volatile u32 good_insns_64[256 / 32] = {
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static u32 good_insns_64[256 / 32] = {
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/* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
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/* ---------------------------------------------- */
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W(0x00, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0) | /* 00 */
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@@ -81,7 +80,7 @@ static volatile u32 good_insns_64[256 / 32] = {
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/* Good-instruction tables for 32-bit apps */
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static volatile u32 good_insns_32[256 / 32] = {
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static u32 good_insns_32[256 / 32] = {
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/* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
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/* ---------------------------------------------- */
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W(0x00, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0) | /* 00 */
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@@ -105,7 +104,7 @@ static volatile u32 good_insns_32[256 / 32] = {
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};
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/* Using this for both 64-bit and 32-bit apps */
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static volatile u32 good_2byte_insns[256 / 32] = {
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static u32 good_2byte_insns[256 / 32] = {
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/* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
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/* ---------------------------------------------- */
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W(0x00, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1) | /* 00 */
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@@ -132,42 +131,47 @@ static volatile u32 good_2byte_insns[256 / 32] = {
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/*
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* opcodes we'll probably never support:
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* 6c-6d, e4-e5, ec-ed - in
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* 6e-6f, e6-e7, ee-ef - out
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* cc, cd - int3, int
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* cf - iret
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* d6 - illegal instruction
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* f1 - int1/icebp
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* f4 - hlt
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* fa, fb - cli, sti
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* 0f - lar, lsl, syscall, clts, sysret, sysenter, sysexit, invd, wbinvd, ud2
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*
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* 6c-6d, e4-e5, ec-ed - in
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* 6e-6f, e6-e7, ee-ef - out
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* cc, cd - int3, int
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* cf - iret
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* d6 - illegal instruction
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* f1 - int1/icebp
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* f4 - hlt
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* fa, fb - cli, sti
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* 0f - lar, lsl, syscall, clts, sysret, sysenter, sysexit, invd, wbinvd, ud2
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*
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* invalid opcodes in 64-bit mode:
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* 06, 0e, 16, 1e, 27, 2f, 37, 3f, 60-62, 82, c4-c5, d4-d5
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*
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* 63 - we support this opcode in x86_64 but not in i386.
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* 06, 0e, 16, 1e, 27, 2f, 37, 3f, 60-62, 82, c4-c5, d4-d5
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* 63 - we support this opcode in x86_64 but not in i386.
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*
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* opcodes we may need to refine support for:
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* 0f - 2-byte instructions: For many of these instructions, the validity
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* depends on the prefix and/or the reg field. On such instructions, we
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* just consider the opcode combination valid if it corresponds to any
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* valid instruction.
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* 8f - Group 1 - only reg = 0 is OK
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* c6-c7 - Group 11 - only reg = 0 is OK
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* d9-df - fpu insns with some illegal encodings
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* f2, f3 - repnz, repz prefixes. These are also the first byte for
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* certain floating-point instructions, such as addsd.
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* fe - Group 4 - only reg = 0 or 1 is OK
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* ff - Group 5 - only reg = 0-6 is OK
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*
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* 0f - 2-byte instructions: For many of these instructions, the validity
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* depends on the prefix and/or the reg field. On such instructions, we
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* just consider the opcode combination valid if it corresponds to any
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* valid instruction.
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*
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* 8f - Group 1 - only reg = 0 is OK
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* c6-c7 - Group 11 - only reg = 0 is OK
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* d9-df - fpu insns with some illegal encodings
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* f2, f3 - repnz, repz prefixes. These are also the first byte for
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* certain floating-point instructions, such as addsd.
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*
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* fe - Group 4 - only reg = 0 or 1 is OK
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* ff - Group 5 - only reg = 0-6 is OK
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*
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* others -- Do we need to support these?
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* 0f - (floating-point?) prefetch instructions
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* 07, 17, 1f - pop es, pop ss, pop ds
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* 26, 2e, 36, 3e - es:, cs:, ss:, ds: segment prefixes --
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*
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* 0f - (floating-point?) prefetch instructions
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* 07, 17, 1f - pop es, pop ss, pop ds
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* 26, 2e, 36, 3e - es:, cs:, ss:, ds: segment prefixes --
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* but 64 and 65 (fs: and gs:) seem to be used, so we support them
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* 67 - addr16 prefix
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* ce - into
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* f0 - lock prefix
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* 67 - addr16 prefix
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* ce - into
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* f0 - lock prefix
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*/
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/*
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@@ -182,11 +186,11 @@ static bool is_prefix_bad(struct insn *insn)
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for (i = 0; i < insn->prefixes.nbytes; i++) {
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switch (insn->prefixes.bytes[i]) {
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case 0x26: /*INAT_PFX_ES */
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case 0x2E: /*INAT_PFX_CS */
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case 0x36: /*INAT_PFX_DS */
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case 0x3E: /*INAT_PFX_SS */
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case 0xF0: /*INAT_PFX_LOCK */
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case 0x26: /* INAT_PFX_ES */
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case 0x2E: /* INAT_PFX_CS */
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case 0x36: /* INAT_PFX_DS */
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case 0x3E: /* INAT_PFX_SS */
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case 0xF0: /* INAT_PFX_LOCK */
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return true;
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}
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}
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@@ -201,12 +205,15 @@ static int validate_insn_32bits(struct uprobe *uprobe, struct insn *insn)
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insn_get_opcode(insn);
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if (is_prefix_bad(insn))
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return -ENOTSUPP;
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if (test_bit(OPCODE1(insn), (unsigned long *)good_insns_32))
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return 0;
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if (insn->opcode.nbytes == 2) {
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if (test_bit(OPCODE2(insn), (unsigned long *)good_2byte_insns))
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return 0;
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}
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return -ENOTSUPP;
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}
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@@ -282,12 +289,12 @@ static void prepare_fixups(struct uprobe *uprobe, struct insn *insn)
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* disastrous.
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*
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* Some useful facts about rip-relative instructions:
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* - There's always a modrm byte.
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* - There's never a SIB byte.
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* - The displacement is always 4 bytes.
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*
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* - There's always a modrm byte.
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* - There's never a SIB byte.
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* - The displacement is always 4 bytes.
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*/
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static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe,
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struct insn *insn)
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static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn)
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{
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u8 *cursor;
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u8 reg;
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@@ -342,13 +349,12 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe,
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}
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/* Target address = address of next instruction + (signed) offset */
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uprobe->arch_info.rip_rela_target_address = (long)insn->length
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+ insn->displacement.value;
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uprobe->arch_info.rip_rela_target_address = (long)insn->length + insn->displacement.value;
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/* Displacement field is gone; slide immediate field (if any) over. */
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if (insn->immediate.nbytes) {
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cursor++;
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memmove(cursor, cursor + insn->displacement.nbytes,
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insn->immediate.nbytes);
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memmove(cursor, cursor + insn->displacement.nbytes, insn->immediate.nbytes);
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}
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return;
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}
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@@ -361,8 +367,10 @@ static int validate_insn_64bits(struct uprobe *uprobe, struct insn *insn)
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insn_get_opcode(insn);
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if (is_prefix_bad(insn))
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return -ENOTSUPP;
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if (test_bit(OPCODE1(insn), (unsigned long *)good_insns_64))
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return 0;
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if (insn->opcode.nbytes == 2) {
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if (test_bit(OPCODE2(insn), (unsigned long *)good_2byte_insns))
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return 0;
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@@ -370,34 +378,31 @@ static int validate_insn_64bits(struct uprobe *uprobe, struct insn *insn)
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return -ENOTSUPP;
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}
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static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe,
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struct insn *insn)
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static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn)
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{
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if (mm->context.ia32_compat)
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return validate_insn_32bits(uprobe, insn);
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return validate_insn_64bits(uprobe, insn);
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}
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#else
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static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe,
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struct insn *insn)
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#else /* 32-bit: */
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static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn)
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{
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return;
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/* No RIP-relative addressing on 32-bit */
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}
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static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe,
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struct insn *insn)
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static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn)
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{
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return validate_insn_32bits(uprobe, insn);
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}
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#endif /* CONFIG_X86_64 */
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/**
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* analyze_insn - instruction analysis including validity and fixups.
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* arch_uprobes_analyze_insn - instruction analysis including validity and fixups.
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* @mm: the probed address space.
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* @uprobe: the probepoint information.
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* Return 0 on success or a -ve number on error.
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*/
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int analyze_insn(struct mm_struct *mm, struct uprobe *uprobe)
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int arch_uprobes_analyze_insn(struct mm_struct *mm, struct uprobe *uprobe)
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{
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int ret;
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struct insn insn;
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@@ -406,7 +411,9 @@ int analyze_insn(struct mm_struct *mm, struct uprobe *uprobe)
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ret = validate_insn_bits(mm, uprobe, &insn);
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if (ret != 0)
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return ret;
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handle_riprel_insn(mm, uprobe, &insn);
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prepare_fixups(uprobe, &insn);
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return 0;
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}
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+13
-15
@@ -1,7 +1,7 @@
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#ifndef _LINUX_UPROBES_H
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#define _LINUX_UPROBES_H
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/*
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* Userspace Probes (UProbes)
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* User-space Probes (UProbes)
|
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*
|
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* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License as published by
|
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@@ -40,8 +40,10 @@ struct uprobe_arch_info {};
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#define uprobe_opcode_sz sizeof(uprobe_opcode_t)
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/* flags that denote/change uprobes behaviour */
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/* Have a copy of original instruction */
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#define UPROBES_COPY_INSN 0x1
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/* Dont run handlers when first register/ last unregister in progress*/
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#define UPROBES_RUN_HANDLER 0x2
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@@ -70,27 +72,23 @@ struct uprobe {
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};
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#ifdef CONFIG_UPROBES
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extern int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe,
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unsigned long vaddr);
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extern int __weak set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe,
|
||||
unsigned long vaddr, bool verify);
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||||
extern int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr);
|
||||
extern int __weak set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr, bool verify);
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||||
extern bool __weak is_bkpt_insn(uprobe_opcode_t *insn);
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||||
extern int register_uprobe(struct inode *inode, loff_t offset,
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||||
struct uprobe_consumer *consumer);
|
||||
extern void unregister_uprobe(struct inode *inode, loff_t offset,
|
||||
struct uprobe_consumer *consumer);
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||||
extern int mmap_uprobe(struct vm_area_struct *vma);
|
||||
extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer);
|
||||
extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer);
|
||||
extern int uprobe_mmap(struct vm_area_struct *vma);
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||||
#else /* CONFIG_UPROBES is not defined */
|
||||
static inline int register_uprobe(struct inode *inode, loff_t offset,
|
||||
struct uprobe_consumer *consumer)
|
||||
static inline int
|
||||
uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer)
|
||||
{
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||||
return -ENOSYS;
|
||||
}
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||||
static inline void unregister_uprobe(struct inode *inode, loff_t offset,
|
||||
struct uprobe_consumer *consumer)
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||||
static inline void
|
||||
uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer)
|
||||
{
|
||||
}
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||||
static inline int mmap_uprobe(struct vm_area_struct *vma)
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||||
static inline int uprobe_mmap(struct vm_area_struct *vma)
|
||||
{
|
||||
return 0;
|
||||
}
|
||||
|
||||
+127
-92
File diff suppressed because it is too large
Load Diff
@@ -618,10 +618,10 @@ again: remove_next = 1 + (end > next->vm_end);
|
||||
mutex_unlock(&mapping->i_mmap_mutex);
|
||||
|
||||
if (root) {
|
||||
mmap_uprobe(vma);
|
||||
uprobe_mmap(vma);
|
||||
|
||||
if (adjust_next)
|
||||
mmap_uprobe(next);
|
||||
uprobe_mmap(next);
|
||||
}
|
||||
|
||||
if (remove_next) {
|
||||
@@ -646,7 +646,7 @@ again: remove_next = 1 + (end > next->vm_end);
|
||||
}
|
||||
}
|
||||
if (insert && file)
|
||||
mmap_uprobe(insert);
|
||||
uprobe_mmap(insert);
|
||||
|
||||
validate_mm(mm);
|
||||
|
||||
@@ -1340,7 +1340,7 @@ out:
|
||||
} else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK))
|
||||
make_pages_present(addr, addr + len);
|
||||
|
||||
if (file && mmap_uprobe(vma))
|
||||
if (file && uprobe_mmap(vma))
|
||||
/* matching probes but cannot insert */
|
||||
goto unmap_and_free_vma;
|
||||
|
||||
@@ -2301,7 +2301,7 @@ int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
|
||||
security_vm_enough_memory_mm(mm, vma_pages(vma)))
|
||||
return -ENOMEM;
|
||||
|
||||
if (vma->vm_file && mmap_uprobe(vma))
|
||||
if (vma->vm_file && uprobe_mmap(vma))
|
||||
return -EINVAL;
|
||||
|
||||
vma_link(mm, vma, prev, rb_link, rb_parent);
|
||||
@@ -2374,7 +2374,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
|
||||
if (new_vma->vm_file) {
|
||||
get_file(new_vma->vm_file);
|
||||
|
||||
if (mmap_uprobe(new_vma))
|
||||
if (uprobe_mmap(new_vma))
|
||||
goto out_free_mempol;
|
||||
|
||||
if (vma->vm_flags & VM_EXECUTABLE)
|
||||
|
||||
Reference in New Issue
Block a user