From c239c83ed5c558be3b5926c7f11639f02c8acd00 Mon Sep 17 00:00:00 2001 From: Sven Schnelle Date: Tue, 20 Feb 2024 14:21:14 +0100 Subject: s390/entry: add CIF_SIE flag and remove sie64a() address check When a program check, interrupt or machine check is triggered, the PSW address is compared to a certain range of the sie64a() function to figure out whether SIE was interrupted and a cleanup of SIE is needed. This doesn't work with kprobes: If kprobes probes an instruction, it copies the instruction to the kprobes instruction page and overwrites the original instruction with an undefind instruction (Opcode 00). When this instruction is hit later, kprobes single-steps the instruction on the kprobes_instruction page. However, if this instruction is a relative branch instruction it will now point to a different location in memory due to being moved to the kprobes instruction page. If the new branch target points into sie64a() the kernel assumes it interrupted SIE when processing the breakpoint and will crash trying to access the SIE control block. Instead of comparing the address, introduce a new CIF_SIE flag which indicates whether SIE was interrupted. Signed-off-by: Sven Schnelle Suggested-by: Heiko Carstens Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens --- arch/s390/include/asm/processor.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/s390/include/asm/processor.h') diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h index 7cf00cf8fb0b..db9982f0e8cd 100644 --- a/arch/s390/include/asm/processor.h +++ b/arch/s390/include/asm/processor.h @@ -14,11 +14,13 @@ #include +#define CIF_SIE 0 /* CPU needs SIE exit cleanup */ #define CIF_NOHZ_DELAY 2 /* delay HZ disable for a tick */ #define CIF_ENABLED_WAIT 5 /* in enabled wait state */ #define CIF_MCCK_GUEST 6 /* machine check happening in guest */ #define CIF_DEDICATED_CPU 7 /* this CPU is dedicated */ +#define _CIF_SIE BIT(CIF_SIE) #define _CIF_NOHZ_DELAY BIT(CIF_NOHZ_DELAY) #define _CIF_ENABLED_WAIT BIT(CIF_ENABLED_WAIT) #define _CIF_MCCK_GUEST BIT(CIF_MCCK_GUEST) -- cgit v1.2.3