[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v4 10/19] xen/arm32: Use alternative to skip the check of pending serrors
We have provided an option to administrator to determine how to handle the SErrors. In order to skip the check of pending SError, in conventional way, we have to read the option every time before we try to check the pending SError. This will add overhead to check the option at every trap. The ARM32 supports the alternative patching feature. We can use an ALTERNATIVE to avoid checking option at every trap. We added a new cpufeature named "SKIP_SYNCHRONIZE_SERROR_ENTRY_EXIT". This feature will be enabled when the option is not diverse. Signed-off-by: Wei Chen <Wei.Chen@xxxxxxx> Reviewed-by: Julien Grall <julien.grall@xxxxxxx> --- xen/arch/arm/arm32/entry.S | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/xen/arch/arm/arm32/entry.S b/xen/arch/arm/arm32/entry.S index 2187226..8cd2123 100644 --- a/xen/arch/arm/arm32/entry.S +++ b/xen/arch/arm/arm32/entry.S @@ -1,5 +1,6 @@ #include <asm/asm_defns.h> #include <asm/regs.h> +#include <asm/alternative.h> #include <public/xen.h> #define SAVE_ONE_BANKED(reg) mrs r11, reg; str r11, [sp, #UREGS_##reg] @@ -44,6 +45,14 @@ save_guest_regs: SAVE_BANKED(fiq) SAVE_ONE_BANKED(R8_fiq); SAVE_ONE_BANKED(R9_fiq); SAVE_ONE_BANKED(R10_fiq) SAVE_ONE_BANKED(R11_fiq); SAVE_ONE_BANKED(R12_fiq); + + /* + * If the SKIP_SYNCHRONIZE_SERROR_ENTRY_EXIT has been set in the cpu + * feature, the checking of pending SErrors will be skipped. + */ + ALTERNATIVE("nop", + "b skip_check", + SKIP_SYNCHRONIZE_SERROR_ENTRY_EXIT) /* * Start to check pending virtual abort in the gap of Guest -> HYP * world switch. @@ -99,6 +108,7 @@ abort_guest_exit_end: */ bne return_from_trap +skip_check: mov pc, lr #define DEFINE_TRAP_ENTRY(trap) \ -- 2.7.4 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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