@@ -70,13 +70,6 @@
msr daif, \flags
.endm
-/*
- * Enable and disable debug exceptions.
- */
- .macro disable_dbg
- msr daifset, #8
- .endm
-
.macro enable_dbg
msr daifclr, #8
.endm
@@ -90,9 +83,9 @@
9990:
.endm
+ /* call with debug exceptions masked */
.macro enable_step_tsk, flgs, tmp
tbz \flgs, #TIF_SINGLESTEP, 9990f
- disable_dbg
mrs \tmp, mdscr_el1
orr \tmp, \tmp, #1
msr mdscr_el1, \tmp
@@ -212,6 +212,10 @@ alternative_else_nop_endif
.if \el == 0
ldr x23, [sp, #S_SP] // load return stack pointer
msr sp_el0, x23
+
+ ldr x1, [tsk, #TSK_TI_FLAGS]
+ enable_step_tsk flgs=x1, tmp=x2
+
#ifdef CONFIG_ARM64_ERRATUM_845719
alternative_if ARM64_WORKAROUND_845719
tbz x22, #4, 1f
@@ -750,7 +754,6 @@ ret_fast_syscall:
cbnz x2, ret_fast_syscall_trace
and x2, x1, #_TIF_WORK_MASK
cbnz x2, work_pending
- enable_step_tsk x1, x2
kernel_exit 0
ret_fast_syscall_trace:
enable_irq // enable interrupts
@@ -765,7 +768,6 @@ work_pending:
#ifdef CONFIG_TRACE_IRQFLAGS
bl trace_hardirqs_on // enabled while in userspace
#endif
- ldr x1, [tsk, #TSK_TI_FLAGS] // re-check for single-step
b finish_ret_to_user
/*
* "slow" syscall return path.
@@ -776,7 +778,6 @@ ret_to_user:
and x2, x1, #_TIF_WORK_MASK
cbnz x2, work_pending
finish_ret_to_user:
- enable_step_tsk x1, x2
kernel_exit 0
ENDPROC(ret_to_user)
enable_step_tsk may enable single-step, so needs to mask debug exceptions to prevent us from single-stepping kernel_exit. This should be the callers problem. Earlier cleanup (2a2830703a23) moved disable_step_tsk into kernel_entry. enable_step_tsk has two callers, both immediately before kernel_exit 0. Move the macro call into kernel_exit after local_mask_daif. enable_step_tsk is now only called with debug exceptions masked. This was the last user of disable_dbg, remove it. Signed-off-by: James Morse <james.morse@arm.com> --- arch/arm64/include/asm/assembler.h | 9 +-------- arch/arm64/kernel/entry.S | 7 ++++--- 2 files changed, 5 insertions(+), 11 deletions(-)