The following commit has been merged into the x86/seves branch of tip: Commit-ID: 6b27edd74a5e9669120f7bd0ae1f475d124c1042 Gitweb: https://git.kernel.org/tip/6b27edd74a5e9669120f7bd0ae1f475d124c1042 Author: Joerg Roedel <jroe...@suse.de> AuthorDate: Mon, 07 Sep 2020 15:15:45 +02:00 Committer: Borislav Petkov <b...@suse.de> CommitterDate: Wed, 09 Sep 2020 11:33:19 +02:00
x86/dumpstack/64: Add noinstr version of get_stack_info() The get_stack_info() functionality is needed in the entry code for the #VC exception handler. Provide a version of it in the .text.noinstr section which can be called safely from there. Signed-off-by: Joerg Roedel <jroe...@suse.de> Signed-off-by: Borislav Petkov <b...@suse.de> Link: https://lkml.kernel.org/r/20200907131613.12703-45-j...@8bytes.org --- arch/x86/include/asm/stacktrace.h | 2 ++- arch/x86/kernel/dumpstack.c | 7 +++--- arch/x86/kernel/dumpstack_64.c | 38 +++++++++++++++++------------- arch/x86/mm/cpu_entry_area.c | 3 +- 4 files changed, 30 insertions(+), 20 deletions(-) diff --git a/arch/x86/include/asm/stacktrace.h b/arch/x86/include/asm/stacktrace.h index 5ae5a68..4960064 100644 --- a/arch/x86/include/asm/stacktrace.h +++ b/arch/x86/include/asm/stacktrace.h @@ -35,6 +35,8 @@ bool in_entry_stack(unsigned long *stack, struct stack_info *info); int get_stack_info(unsigned long *stack, struct task_struct *task, struct stack_info *info, unsigned long *visit_mask); +bool get_stack_info_noinstr(unsigned long *stack, struct task_struct *task, + struct stack_info *info); const char *stack_type_name(enum stack_type type); diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index 48ce445..74147f7 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -29,8 +29,8 @@ static int die_counter; static struct pt_regs exec_summary_regs; -bool in_task_stack(unsigned long *stack, struct task_struct *task, - struct stack_info *info) +bool noinstr in_task_stack(unsigned long *stack, struct task_struct *task, + struct stack_info *info) { unsigned long *begin = task_stack_page(task); unsigned long *end = task_stack_page(task) + THREAD_SIZE; @@ -46,7 +46,8 @@ bool in_task_stack(unsigned long *stack, struct task_struct *task, return true; } -bool in_entry_stack(unsigned long *stack, struct stack_info *info) +/* Called from get_stack_info_noinstr - so must be noinstr too */ +bool noinstr in_entry_stack(unsigned long *stack, struct stack_info *info) { struct entry_stack *ss = cpu_entry_stack(smp_processor_id()); diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index c49cf59..1dd8513 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -85,7 +85,7 @@ struct estack_pages estack_pages[CEA_ESTACK_PAGES] ____cacheline_aligned = { EPAGERANGE(VC2), }; -static bool in_exception_stack(unsigned long *stack, struct stack_info *info) +static __always_inline bool in_exception_stack(unsigned long *stack, struct stack_info *info) { unsigned long begin, end, stk = (unsigned long)stack; const struct estack_pages *ep; @@ -126,7 +126,7 @@ static bool in_exception_stack(unsigned long *stack, struct stack_info *info) return true; } -static bool in_irq_stack(unsigned long *stack, struct stack_info *info) +static __always_inline bool in_irq_stack(unsigned long *stack, struct stack_info *info) { unsigned long *end = (unsigned long *)this_cpu_read(hardirq_stack_ptr); unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long)); @@ -151,32 +151,38 @@ static bool in_irq_stack(unsigned long *stack, struct stack_info *info) return true; } -int get_stack_info(unsigned long *stack, struct task_struct *task, - struct stack_info *info, unsigned long *visit_mask) +bool noinstr get_stack_info_noinstr(unsigned long *stack, struct task_struct *task, + struct stack_info *info) { - if (!stack) - goto unknown; - - task = task ? : current; - if (in_task_stack(stack, task, info)) - goto recursion_check; + return true; if (task != current) - goto unknown; + return false; if (in_exception_stack(stack, info)) - goto recursion_check; + return true; if (in_irq_stack(stack, info)) - goto recursion_check; + return true; if (in_entry_stack(stack, info)) - goto recursion_check; + return true; + + return false; +} + +int get_stack_info(unsigned long *stack, struct task_struct *task, + struct stack_info *info, unsigned long *visit_mask) +{ + task = task ? : current; - goto unknown; + if (!stack) + goto unknown; + + if (!get_stack_info_noinstr(stack, task, info)) + goto unknown; -recursion_check: /* * Make sure we don't iterate through any given stack more than once. * If it comes up a second time then there's something wrong going on: diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c index 770b613..f5e1e60 100644 --- a/arch/x86/mm/cpu_entry_area.c +++ b/arch/x86/mm/cpu_entry_area.c @@ -21,7 +21,8 @@ DEFINE_PER_CPU(struct cea_exception_stacks*, cea_exception_stacks); DECLARE_PER_CPU_PAGE_ALIGNED(struct doublefault_stack, doublefault_stack); #endif -struct cpu_entry_area *get_cpu_entry_area(int cpu) +/* Is called from entry code, so must be noinstr */ +noinstr struct cpu_entry_area *get_cpu_entry_area(int cpu) { unsigned long va = CPU_ENTRY_AREA_PER_CPU + cpu * CPU_ENTRY_AREA_SIZE; BUILD_BUG_ON(sizeof(struct cpu_entry_area) % PAGE_SIZE != 0);
