From 51077e03b8cef2a24d6582b8c54b718fced6878c Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Fri, 25 Oct 2019 17:42:12 +0100 Subject: [PATCH] arm64: add local_daif_inherit() Some synchronous exceptions can be taken from a number of contexts, e.g. where IRQs may or may not be masked. In the entry assembly for these exceptions, we use the inherit_daif assembly macro to ensure that we only mask those exceptions which were masked when the exception was taken. So that we can do the same from C code, this patch adds a new local_daif_inherit() function, following the existing local_daif_*() naming scheme. Signed-off-by: Mark Rutland [moved away from local_daif_restore()] Signed-off-by: James Morse Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/daifflags.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/arch/arm64/include/asm/daifflags.h b/arch/arm64/include/asm/daifflags.h index 063c964..9207cd5 100644 --- a/arch/arm64/include/asm/daifflags.h +++ b/arch/arm64/include/asm/daifflags.h @@ -9,6 +9,7 @@ #include #include +#include #define DAIF_PROCCTX 0 #define DAIF_PROCCTX_NOIRQ PSR_I_BIT @@ -109,4 +110,19 @@ static inline void local_daif_restore(unsigned long flags) trace_hardirqs_off(); } +/* + * Called by synchronous exception handlers to restore the DAIF bits that were + * modified by taking an exception. + */ +static inline void local_daif_inherit(struct pt_regs *regs) +{ + unsigned long flags = regs->pstate & DAIF_MASK; + + /* + * We can't use local_daif_restore(regs->pstate) here as + * system_has_prio_mask_debugging() won't restore the I bit if it can + * use the pmr instead. + */ + write_sysreg(flags, daif); +} #endif -- 2.7.4