From: Rohan McLure <rmclure@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Rohan McLure <rmclure@linux.ibm.com>
Subject: [PATCH 23/23] powerpc/64e: Clear gprs on interrupt routine entry on Book3E
Date: Fri, 16 Sep 2022 15:33:00 +1000 [thread overview]
Message-ID: <20220916053300.786330-24-rmclure@linux.ibm.com> (raw)
In-Reply-To: <20220916053300.786330-1-rmclure@linux.ibm.com>
Zero GPRS r14-r31 on entry into the kernel for interrupt sources to
limit influence of user-space values in potential speculation gadgets.
Prior to this commit, all other GPRS are reassigned during the common
prologue to interrupt handlers and so need not be zeroised explicitly.
This may be done safely, without loss of register state prior to the
interrupt, as the common prologue saves the initial values of
non-volatiles, which are unconditionally restored in interrupt_64.S.
Mitigation defaults to enabled by INTERRUPT_SANITIZE_REGISTERS.
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
---
V3 -> V4: New patch.
V4 -> V5: Depend on Kconfig option. Remove ZEROIZE_NVGPRS on bad kernel
stack handler.
---
arch/powerpc/kernel/exceptions-64e.S | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
index 48c640ca425d..61748769ea29 100644
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -365,6 +365,11 @@ ret_from_mc_except:
std r14,PACA_EXMC+EX_R14(r13); \
std r15,PACA_EXMC+EX_R15(r13)
+#ifdef CONFIG_INTERRUPT_SANITIZE_REGISTERS
+#define SANITIZE_NVGPRS ZEROIZE_NVGPRS()
+#else
+#define SANITIZE_NVGPRS
+#endif
/* Core exception code for all exceptions except TLB misses. */
#define EXCEPTION_COMMON_LVL(n, scratch, excf) \
@@ -401,7 +406,8 @@ exc_##n##_common: \
std r12,STACK_FRAME_OVERHEAD-16(r1); /* mark the frame */ \
std r3,_TRAP(r1); /* set trap number */ \
std r0,RESULT(r1); /* clear regs->result */ \
- SAVE_NVGPRS(r1);
+ SAVE_NVGPRS(r1); \
+ SANITIZE_NVGPRS; /* minimise speculation influence */
#define EXCEPTION_COMMON(n) \
EXCEPTION_COMMON_LVL(n, SPRN_SPRG_GEN_SCRATCH, PACA_EXGEN)
--
2.34.1
next prev parent reply other threads:[~2022-09-16 5:33 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-16 5:32 [PATCH 00/23] powerpc: Syscall wrapper and register clearing Rohan McLure
2022-09-16 5:32 ` [PATCH 01/23] powerpc: Remove asmlinkage from syscall handler definitions Rohan McLure
2022-09-16 5:32 ` [PATCH 02/23] powerpc: Save caller r3 prior to system_call_exception Rohan McLure
2022-09-16 5:32 ` [PATCH 03/23] powerpc: Add ZEROIZE_GPRS macros for register clears Rohan McLure
2022-09-16 5:32 ` [PATCH 04/23] powerpc/64s: Use {ZEROIZE,SAVE,REST}_GPRS macros in sc, scv 0 handlers Rohan McLure
2022-09-16 5:32 ` [PATCH 05/23] powerpc/32: Clarify interrupt restores with REST_GPR macro in entry_32.S Rohan McLure
2022-09-20 0:51 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 06/23] powerpc/64e: Clarify register saves and clears with {SAVE,ZEROIZE}_GPRS Rohan McLure
2022-09-20 0:55 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 07/23] powerpc/64s: Fix comment on interrupt handler prologue Rohan McLure
2022-09-20 0:55 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 08/23] powerpc: Fix fallocate and fadvise64_64 compat parameter combination Rohan McLure
2022-09-16 6:54 ` Arnd Bergmann
2022-09-20 1:01 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 09/23] asm-generic: compat: Support BE for long long args in 32-bit ABIs Rohan McLure
2022-09-20 1:06 ` Nicholas Piggin
2022-09-20 7:09 ` Arnd Bergmann
2022-09-16 5:32 ` [PATCH 10/23] powerpc: Use generic fallocate compatibility syscall Rohan McLure
2022-09-16 6:56 ` Arnd Bergmann
2022-09-16 5:32 ` [PATCH 11/23] powerpc/32: Remove powerpc select specialisation Rohan McLure
2022-09-16 5:32 ` [PATCH 12/23] powerpc: Remove direct call to personality syscall handler Rohan McLure
2022-09-16 5:32 ` [PATCH 13/23] powerpc: Remove direct call to mmap2 syscall handlers Rohan McLure
2022-09-16 5:32 ` [PATCH 14/23] powerpc: Provide do_ppc64_personality helper Rohan McLure
2022-09-16 5:32 ` [PATCH 15/23] powerpc: Adopt SYSCALL_DEFINE for arch-specific syscall handlers Rohan McLure
2022-09-16 5:48 ` Rohan McLure
2022-09-20 1:24 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 16/23] powerpc: Include all arch-specific syscall prototypes Rohan McLure
2022-09-20 1:27 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 17/23] powerpc: Enable compile-time check for syscall handlers Rohan McLure
2022-09-20 1:30 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 18/23] powerpc: Use common syscall handler type Rohan McLure
2022-09-20 1:39 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 19/23] powerpc: Provide syscall wrapper Rohan McLure
2022-09-20 1:59 ` Nicholas Piggin
2022-09-21 3:44 ` Rohan McLure
2022-09-16 5:32 ` [PATCH 20/23] powerpc/64s: Clear/restore caller gprs in syscall interrupt/return Rohan McLure
2022-09-20 2:03 ` Nicholas Piggin
2022-09-20 4:54 ` Rohan McLure
2022-09-21 5:33 ` Rohan McLure
2022-09-20 2:07 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 21/23] powerpc/64: Add INTERRUPT_SANITIZE_REGISTERS Kconfig Rohan McLure
2022-09-20 2:10 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 22/23] powerpc/64s: Clear gprs on interrupt routine entry in Book3S Rohan McLure
2022-09-20 2:27 ` Nicholas Piggin
2022-09-16 5:33 ` Rohan McLure [this message]
2022-09-16 5:58 ` [PATCH 00/23] powerpc: Syscall wrapper and register clearing Rohan McLure
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