We are not working with values from MSR that's why
we can discard it and use r11 for different purpose without
saving/restoring.
Signed-off-by: Michal Simek <monstr@monstr.eu>
Remove set_vms because UMS is cleared and VMS is already setup.
Optimize function calling which save one additional instruction.
Signed-off-by: Michal Simek <monstr@monstr.eu>
VMS is always setup because VM mode was before
exception/syscall/interrupt. Kernel continues in kernel mode
that's why we have to clear UMS bit if kernel comes from
user space.
Signed-off-by: Michal Simek <monstr@monstr.eu>
PT_MODE stores information if kernel comes from user
or kernel space. If come from user space, PT_MODE
contains 0. If come from kernel store, PT_MODE contains
non zero value. We don't need to save value 1. I am using
r1 register which contains non zero value.
This change save one additional instruction.
Signed-off-by: Michal Simek <monstr@monstr.eu>
Keep together all arguments for send_sig function.
Move returning address to delay slot which is executed.
Remove additional send_sig loading. I am using IMM part of
rtbd instruction with r0.
old solution:
addik r11, r0, send_sig
rtbd r11, 0
nop
new solution:
rtbd r0, send_sig
nop
There is one instruction saving.
Signed-off-by: Michal Simek <monstr@monstr.eu>
It is necessary to setup BIP and EE and clear EIP
only for unaligned exception handler. The rest of
hw exception handlers don't require it.
HW exception occured and we are not in virtual mode.
That's why we can do operations protected by EIP.
Interrupt, next hw exception or syscall can't occur.
EIP is cleared by rted.
This change speedup page_fault hw exception handler
which is critical path.
There is also necessary to save R11 content before
flag setup for unaligned exception.
Signed-off-by: Michal Simek <monstr@monstr.eu>
SAVE_STATE macro is used in hw exceptions high level handling
functions. Hw exception doesn't disable IRQ that's why we don't
need to reenable it.
Signed-off-by: Michal Simek <monstr@monstr.eu>
We don't need to protect by BIP whole ret_from_trap/ret_from_exc code.
Only restoring from user/hw exception should be covered.
If BIP is setup, IRQ can't occur.
Signed-off-by: Michal Simek <monstr@monstr.eu>
There is a way howto remove Kernel Mode variable. It is easier
to parse UMS bit in MSR to find out if I come from kernel or user
space. Loading MSR content should be in one cycle and loading
PER_CPU variable depends on memory state.
Signed-off-by: Michal Simek <monstr@monstr.eu>
Save and restore R3/R4 registers in macros. This change
help to cleanup entry.S.
In ret_from_trap function we are saving returning value from
syscall to pt_regs on stack that's why we don't need to save and
restore these values before kernel functions (schedule, do_signal).
Signed-off-by: Michal Simek <monstr@monstr.eu>
_start symbol stores physical address where kernel is.
Gdb uses this symbol for their purpose that's why
we have to rename it.
Signed-off-by: Michal Simek <monstr@monstr.eu>
Michal Simek