From cbf892ba56677b942020d2bc7ca9b79281fa0bcc Mon Sep 17 00:00:00 2001 From: Rohan McLure Date: Thu, 1 Dec 2022 18:10:14 +1100 Subject: [PATCH] powerpc/64: Add interrupt register sanitisation macros Include in asm/ppc_asm.h macros to be used in multiple successive patches to implement zeroising architected registers in interrupt handlers. Registers will be sanitised in this fashion in future patches to reduce the speculation influence of user-controlled register values. These mitigations will be configurable through the CONFIG_INTERRUPT_SANITIZE_REGISTERS Kconfig option. Included are macros for conditionally zeroising registers and restoring as required with the mitigation enabled. With the mitigation disabled, non-volatiles must be restored on demand at separate locations to those required by the mitigation. Reviewed-by: Nicholas Piggin Signed-off-by: Rohan McLure Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221201071019.1953023-2-rmclure@linux.ibm.com --- arch/powerpc/include/asm/ppc_asm.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h index 753a2757bcd4f..d2f44612f4b02 100644 --- a/arch/powerpc/include/asm/ppc_asm.h +++ b/arch/powerpc/include/asm/ppc_asm.h @@ -74,6 +74,25 @@ #define SAVE_GPR(n, base) SAVE_GPRS(n, n, base) #define REST_GPR(n, base) REST_GPRS(n, n, base) +/* macros for handling user register sanitisation */ +#ifdef CONFIG_INTERRUPT_SANITIZE_REGISTERS +#define SANITIZE_SYSCALL_GPRS() ZEROIZE_GPR(0); \ + ZEROIZE_GPRS(5, 12); \ + ZEROIZE_NVGPRS() +#define SANITIZE_GPR(n) ZEROIZE_GPR(n) +#define SANITIZE_GPRS(start, end) ZEROIZE_GPRS(start, end) +#define SANITIZE_NVGPRS() ZEROIZE_NVGPRS() +#define SANITIZE_RESTORE_NVGPRS() REST_NVGPRS(r1) +#define HANDLER_RESTORE_NVGPRS() +#else +#define SANITIZE_SYSCALL_GPRS() +#define SANITIZE_GPR(n) +#define SANITIZE_GPRS(start, end) +#define SANITIZE_NVGPRS() +#define SANITIZE_RESTORE_NVGPRS() +#define HANDLER_RESTORE_NVGPRS() REST_NVGPRS(r1) +#endif /* CONFIG_INTERRUPT_SANITIZE_REGISTERS */ + #define SAVE_FPR(n, base) stfd n,8*TS_FPRWIDTH*(n)(base) #define SAVE_2FPRS(n, base) SAVE_FPR(n, base); SAVE_FPR(n+1, base) #define SAVE_4FPRS(n, base) SAVE_2FPRS(n, base); SAVE_2FPRS(n+2, base) -- 2.30.2