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[193.116.106.251]) by smtp.gmail.com with ESMTPSA id d62-20020a623641000000b005627ddbc7a4sm3599599pfa.191.2022.10.30.22.55.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 30 Oct 2022 22:55:23 -0700 (PDT) From: Nicholas Piggin To: linuxppc-dev@lists.ozlabs.org Subject: [RFC PATCH 14/19] powerpc: split validate_sp into two functions Date: Mon, 31 Oct 2022 15:54:35 +1000 Message-Id: <20221031055440.3594315-15-npiggin@gmail.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20221031055440.3594315-1-npiggin@gmail.com> References: <20221031055440.3594315-1-npiggin@gmail.com> MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Most callers just want to validate an arbitrary kernel stack pointer, some need a particular size. Make the size case the exceptional one with an extra function. Signed-off-by: Nicholas Piggin --- arch/powerpc/include/asm/processor.h | 15 ++++++++++++--- arch/powerpc/kernel/process.c | 23 ++++++++++++++--------- arch/powerpc/kernel/stacktrace.c | 2 +- arch/powerpc/perf/callchain.c | 6 +++--- 4 files changed, 30 insertions(+), 16 deletions(-) diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h index 631802999d59..e96c9b8c2a60 100644 --- a/arch/powerpc/include/asm/processor.h +++ b/arch/powerpc/include/asm/processor.h @@ -374,9 +374,18 @@ static inline unsigned long __pack_fe01(unsigned int fpmode) #endif -/* Check that a certain kernel stack pointer is valid in task_struct p */ -int validate_sp(unsigned long sp, struct task_struct *p, - unsigned long nbytes); +/* + * Check that a certain kernel stack pointer is a valid (minimum sized) + * stack frame in task_struct p. + */ +int validate_sp(unsigned long sp, struct task_struct *p); + +/* + * validate the stack frame of a particular minimum size, used for when we are + * looking at a certain object in the stack beyond the minimum. + */ +int validate_sp_size(unsigned long sp, struct task_struct *p, + unsigned long nbytes); /* * Prefetch macros. diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 6cb3982a11ef..b5defea32e75 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -2128,9 +2128,12 @@ static inline int valid_emergency_stack(unsigned long sp, struct task_struct *p, return 0; } - -int validate_sp(unsigned long sp, struct task_struct *p, - unsigned long nbytes) +/* + * validate the stack frame of a particular minimum size, used for when we are + * looking at a certain object in the stack beyond the minimum. + */ +int validate_sp_size(unsigned long sp, struct task_struct *p, + unsigned long nbytes) { unsigned long stack_page = (unsigned long)task_stack_page(p); @@ -2146,7 +2149,10 @@ int validate_sp(unsigned long sp, struct task_struct *p, return valid_emergency_stack(sp, p, nbytes); } -EXPORT_SYMBOL(validate_sp); +int validate_sp(unsigned long sp, struct task_struct *p) +{ + return validate_sp(sp, p, STACK_FRAME_OVERHEAD); +} static unsigned long ___get_wchan(struct task_struct *p) { @@ -2154,13 +2160,12 @@ static unsigned long ___get_wchan(struct task_struct *p) int count = 0; sp = p->thread.ksp; - if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD)) + if (!validate_sp(sp, p)) return 0; do { sp = READ_ONCE_NOCHECK(*(unsigned long *)sp); - if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD) || - task_is_running(p)) + if (!validate_sp(sp, p) || task_is_running(p)) return 0; if (count > 0) { ip = READ_ONCE_NOCHECK(((unsigned long *)sp)[STACK_FRAME_LR_SAVE]); @@ -2214,7 +2219,7 @@ void __no_sanitize_address show_stack(struct task_struct *tsk, lr = 0; printk("%sCall Trace:\n", loglvl); do { - if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD)) + if (!validate_sp(sp, tsk)) break; stack = (unsigned long *) sp; @@ -2241,7 +2246,7 @@ void __no_sanitize_address show_stack(struct task_struct *tsk, * could hold a pt_regs, if that does not fit then it can't * have regs. */ - if (validate_sp(sp, tsk, STACK_SWITCH_FRAME_SIZE) + if (validate_sp_size(sp, tsk, STACK_SWITCH_FRAME_SIZE) && stack[STACK_INT_FRAME_MARKER_LONGS] == STACK_FRAME_REGS_MARKER) { struct pt_regs *regs = (struct pt_regs *) (sp + STACK_INT_FRAME_REGS); diff --git a/arch/powerpc/kernel/stacktrace.c b/arch/powerpc/kernel/stacktrace.c index 453ac317a6cf..1dbbf30f265e 100644 --- a/arch/powerpc/kernel/stacktrace.c +++ b/arch/powerpc/kernel/stacktrace.c @@ -43,7 +43,7 @@ void __no_sanitize_address arch_stack_walk(stack_trace_consume_fn consume_entry, unsigned long *stack = (unsigned long *) sp; unsigned long newsp, ip; - if (!validate_sp(sp, task, STACK_FRAME_OVERHEAD)) + if (!validate_sp(sp, task)) return; newsp = stack[0]; diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c index b01497ed5173..6b4434dd0ff3 100644 --- a/arch/powerpc/perf/callchain.c +++ b/arch/powerpc/perf/callchain.c @@ -27,7 +27,7 @@ static int valid_next_sp(unsigned long sp, unsigned long prev_sp) { if (sp & 0xf) return 0; /* must be 16-byte aligned */ - if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD)) + if (!validate_sp(sp, current)) return 0; if (sp >= prev_sp + STACK_FRAME_MIN_SIZE) return 1; @@ -53,7 +53,7 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re sp = regs->gpr[1]; perf_callchain_store(entry, perf_instruction_pointer(regs)); - if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD)) + if (!validate_sp(sp, current)) return; for (;;) { @@ -61,7 +61,7 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re next_sp = fp[0]; if (next_sp == sp + STACK_INT_FRAME_SIZE && - validate_sp(sp, current, STACK_INT_FRAME_SIZE) && + validate_sp_size(sp, current, STACK_INT_FRAME_SIZE) && fp[STACK_INT_FRAME_MARKER_LONGS] == STACK_FRAME_REGS_MARKER) { /* * This looks like an interrupt frame for an