diff options
| author | Alexander Shishkin <alexander.shishkin@linux.intel.com> | 2018-06-06 14:54:10 +0200 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2018-08-15 00:12:29 +0200 |
| commit | d83212d5dd6761625fe87cc23016bbaa47303271 (patch) | |
| tree | d6a5e3b56e84938b6f8079bd8622e7b93bfc5326 /arch | |
| parent | kallsyms: Simplify update_iter_mod() (diff) | |
| download | linux-d83212d5dd6761625fe87cc23016bbaa47303271.tar.xz linux-d83212d5dd6761625fe87cc23016bbaa47303271.zip | |
kallsyms, x86: Export addresses of PTI entry trampolines
Currently, the addresses of PTI entry trampolines are not exported to
user space. Kernel profiling tools need these addresses to identify the
kernel code, so add a symbol and address for each CPU's PTI entry
trampoline.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/1528289651-4113-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/mm/cpu_entry_area.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c index b45f5aaefd74..fab49fd5190f 100644 --- a/arch/x86/mm/cpu_entry_area.c +++ b/arch/x86/mm/cpu_entry_area.c @@ -2,6 +2,7 @@ #include <linux/spinlock.h> #include <linux/percpu.h> +#include <linux/kallsyms.h> #include <asm/cpu_entry_area.h> #include <asm/pgtable.h> @@ -150,6 +151,28 @@ static void __init setup_cpu_entry_area(int cpu) percpu_setup_debug_store(cpu); } +#ifdef CONFIG_X86_64 +int arch_get_kallsym(unsigned int symnum, unsigned long *value, char *type, + char *name) +{ + unsigned int cpu, ncpu = 0; + + if (symnum >= num_possible_cpus()) + return -EINVAL; + + for_each_possible_cpu(cpu) { + if (ncpu++ >= symnum) + break; + } + + *value = (unsigned long)&get_cpu_entry_area(cpu)->entry_trampoline; + *type = 't'; + strlcpy(name, "__entry_SYSCALL_64_trampoline", KSYM_NAME_LEN); + + return 0; +} +#endif + static __init void setup_cpu_entry_area_ptes(void) { #ifdef CONFIG_X86_32 |