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authorJames Morse <james.morse@arm.com>2017-11-02 12:12:38 +0000
committerWill Deacon <will.deacon@arm.com>2017-11-02 15:55:41 +0000
commit84d0fb1bb6257d5d5d45f5e3554ab441b4ff5a74 (patch)
tree3054c4b315f1b3963b0ceeeeea140f6d85503933 /arch/arm64/include/asm/assembler.h
parent8d66772e869e79ffb94eed7492ca3d2267e150e8 (diff)
arm64: entry.S: Remove disable_dbg
enable_step_tsk is the only user of disable_dbg, which doesn't respect our 'dai' order for exception masking. enable_step_tsk may enable single-step, so previously needed to mask debug exceptions to prevent us from single-stepping kernel_exit. enable_step_tsk is called at the end of the ret_to_user loop, which has already masked all exceptions so this is no longer needed. Remove disable_dbg, add a comment that enable_step_tsk's caller should have masked debug. Signed-off-by: James Morse <james.morse@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/assembler.h')
-rw-r--r--arch/arm64/include/asm/assembler.h9
1 files changed, 1 insertions, 8 deletions
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index a4aa22241dd1..8bc63fc98752 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -69,13 +69,6 @@
msr daif, \flags
.endm
-/*
- * Enable and disable debug exceptions.
- */
- .macro disable_dbg
- msr daifset, #8
- .endm
-
.macro enable_dbg
msr daifclr, #8
.endm
@@ -89,9 +82,9 @@
9990:
.endm
+ /* call with daif masked */
.macro enable_step_tsk, flgs, tmp
tbz \flgs, #TIF_SINGLESTEP, 9990f
- disable_dbg
mrs \tmp, mdscr_el1
orr \tmp, \tmp, #DBG_MDSCR_SS
msr mdscr_el1, \tmp