diff options
| author | Andy Lutomirski <luto@kernel.org> | 2018-09-03 15:59:43 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-09-08 11:20:11 +0200 |
| commit | 98f05b5138f0a9b56022295cc1387e635b25635d (patch) | |
| tree | e116b364861f976467534b78bbce1771abdebf54 /arch/x86/kernel/process_64.c | |
| parent | bd7b1f7cbf9cb35dab8e1b99145d07afc5b7a132 (diff) | |
x86/entry/64: Use the TSS sp2 slot for SYSCALL/SYSRET scratch space
In the non-trampoline SYSCALL64 path, a percpu variable is used to
temporarily store the user RSP value.
Instead of a separate variable, use the otherwise unused sp2 slot in the
TSS. This will improve cache locality, as the sp1 slot is already used in
the same code to find the kernel stack. It will also simplify a future
change to make the non-trampoline path work in PTI mode.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/08e769a0023dbad4bac6f34f3631dbaf8ad59f4f.1536015544.git.luto@kernel.org
Diffstat (limited to 'arch/x86/kernel/process_64.c')
| -rw-r--r-- | arch/x86/kernel/process_64.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index a451bc374b9b..0fa7aa19f09e 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -59,8 +59,6 @@ #include <asm/unistd_32_ia32.h> #endif -__visible DEFINE_PER_CPU(unsigned long, rsp_scratch); - /* Prints also some state that isn't saved in the pt_regs */ void __show_regs(struct pt_regs *regs, int all) { |