xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

x86/traps: Make interrupt enable/disable symmetric in C code

Browse Source 
Traps enable interrupts conditionally but rely on the ASM return code to
disable them again. That results in redundant interrupt disable and trace
calls.

Make the trap handlers disable interrupts before returning to avoid that,
which allows simplification of the ASM entry code in follow up changes.

Originally-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505134903.622702796@linutronix.de
This commit is contained in:
Thomas Gleixner
2019-10-23 14:27:10 +02:00
parent c9317202af
commit ca4c6a9858
2 changed files with 32 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
arch/x86/mm/fault.c
View File

@@ -786,6 +786,8 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
force_sig_fault(SIGSEGV, si_code, (void __user *)address);
local_irq_disable();
return;
}
@@ -1384,9 +1386,18 @@ do_page_fault(struct pt_regs *regs, unsigned long hw_error_code,
return;
/* Was the fault on kernel-controlled part of the address space? */
if (unlikely(fault_in_kernel_space(address)))
if (unlikely(fault_in_kernel_space(address))) {
do_kern_addr_fault(regs, hw_error_code, address);
else
} else {
do_user_addr_fault(regs, hw_error_code, address);
/*
* User address page fault handling might have reenabled
* interrupts. Fixing up all potential exit points of
* do_user_addr_fault() and its leaf functions is just not
* doable w/o creating an unholy mess or turning the code
* upside down.
*/
local_irq_disable();
}
}
NOKPROBE_SYMBOL(do_page_fault);