tyler.durden
/
audk
mirror of https://github.com/acidanthera/audk.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

ArmPkg/CpuDxe: Disable interrupt before restoring context 

Interrupt must be disabled before we storing ELR and other system
registers, or else ELR will be overridden by interrupt reentrance.

This bug is critical as we may get occasional exception or dead loop
when interrupt reentrance occurs:

  After increasing SP ... Before popping out registers
Or
  After restoring ELR

The 1st circumstance could also be resolved by optimizing SP operation
(Pop out registers before adding SP back), but the 2nd could not be
resolved by disabling interrupt.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Heyi Guo <heyi.guo@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18538 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
Heyi Guo 2015-09-24 17:05:39 +00:00 committed by abiesheuvel
parent be73a0c483
commit 36c64c664b
1 changed files with 8 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
ArmPkg/Drivers/CpuDxe/AArch64/ExceptionSupport.S
View File

@ -358,6 +358,14 @@ ASM_PFX(AsmCommonExceptionEntry):
#define REG_PAIR(REG1, REG2, OFFSET, CONTEXT_SIZE) ldp REG1, REG2, [sp, #(OFFSET-CONTEXT_SIZE)]
#define REG_ONE(REG1, OFFSET, CONTEXT_SIZE) ldur REG1, [sp, #(OFFSET-CONTEXT_SIZE)]
//
// Disable interrupt(IRQ and FIQ) before restoring context,
// or else the context will be corrupted by interrupt reentrance.
// Interrupt mask will be restored from spsr by hardware when we call eret
//
msr daifset, #3
isb
// Adjust SP to pop system registers
add sp, sp, #(GP_CONTEXT_SIZE + FP_CONTEXT_SIZE + SYS_CONTEXT_SIZE)
ALL_SYS_REGS