linux/arch/x86/entry
Andy Lutomirski 98f05b5138 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
2018-09-08 11:20:11 +02:00
..
syscalls x86: Wire up restartable sequence system call 2018-06-06 11:58:32 +02:00
vdso x86/vdso: Fix vDSO build if a retpoline is emitted 2018-08-20 18:04:41 +02:00
vsyscall docs: Fix some broken references 2018-06-15 18:10:01 -03:00
calling.h syscalls/x86: Extend register clearing on syscall entry to lower registers 2018-04-05 16:59:39 +02:00
common.c rseq: Avoid infinite recursion when delivering SIGSEGV 2018-06-22 19:04:22 +02:00
entry_32.S x86/entry/32: Check for VM86 mode in slow-path check 2018-07-20 22:33:41 +02:00
entry_64_compat.S x86/entry/64/compat: Fix "x86/entry/64/compat: Preserve r8-r11 in int $0x80" 2018-06-27 09:35:40 +02:00
entry_64.S x86/entry/64: Use the TSS sp2 slot for SYSCALL/SYSRET scratch space 2018-09-08 11:20:11 +02:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
syscall_32.c syscalls/x86: Unconditionally enable 'struct pt_regs' based syscalls on x86_64 2018-04-05 16:59:38 +02:00
syscall_64.c syscalls/x86: Unconditionally enable 'struct pt_regs' based syscalls on x86_64 2018-04-05 16:59:38 +02:00
thunk_32.S x86: move exports to actual definitions 2016-08-07 23:47:15 -04:00
thunk_64.S x86: move exports to actual definitions 2016-08-07 23:47:15 -04:00