2
0
mirror of https://github.com/edk2-porting/linux-next.git synced 2025-01-20 03:24:03 +08:00
linux-next/arch/x86
George Spelvin 5a33fcb8d9 x86/asm/tsc: Save an instruction in DECLARE_ARGS users
Before, the code to do RDTSC looked like:

  rdtsc
  shl $0x20, %rdx
  mov %eax, %eax
  or  %rdx, %rax

The "mov %eax, %eax" is required to clear the high 32 bits of RAX.

By declaring low and high as 64-bit variables, the code is
simplified to:

  rdtsc
  shl $0x20,%rdx
  or  %rdx,%rax

Yes, it's a 2-byte instruction that's not on a critical path,
but there are principles to be upheld.

Every user of EAX_EDX_RET has been checked. I tried to check
users of EAX_EDX_ARGS, but there weren't any, so I deleted it to
be safe.

( There's no benefit to making "high" 64 bits, but it was the
  simplest way to proceed. )

Signed-off-by: George Spelvin <linux@horizon.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: jacob.jun.pan@linux.intel.com
Link: http://lkml.kernel.org/r/20150618075906.4615.qmail@ns.horizon.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-06 15:23:30 +02:00
..
boot x86/asm/tsc: Rename native_read_tsc() to rdtsc() 2015-07-06 15:23:28 +02:00
configs kconfig: add xenconfig defconfig helper 2015-06-16 11:04:29 +01:00
crypto crypto: aesni - fix failing setkey for rfc4106-gcm-aesni 2015-06-29 16:06:30 +08:00
entry x86/asm/tsc: Add rdtsc_ordered() and use it in trivial call sites 2015-07-06 15:23:29 +02:00
ia32 Merge branch 'x86-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-06-22 17:59:09 -07:00
include x86/asm/tsc: Save an instruction in DECLARE_ARGS users 2015-07-06 15:23:30 +02:00
kernel x86/asm/tsc: Use rdtsc_ordered() in read_tsc() instead of get_cycles() 2015-07-06 15:23:29 +02:00
kvm x86/asm/tsc: Add rdtsc_ordered() and use it in trivial call sites 2015-07-06 15:23:29 +02:00
lguest Merge branch 'x86-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-06-22 17:59:09 -07:00
lib x86/asm/tsc: Add rdtsc_ordered() and use it in trivial call sites 2015-07-06 15:23:29 +02:00
math-emu x86/fpu: Harmonize FPU register state types 2015-05-19 15:48:09 +02:00
mm mm/memblock: add extra "flags" to memblock to allow selection of memory based on attribute 2015-06-24 17:49:44 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2015-06-24 16:49:49 -07:00
oprofile x86/asm/entry: Change all 'user_mode_vm()' calls to 'user_mode()' 2015-03-23 11:14:17 +01:00
pci PCI changes for the v4.2 merge window: 2015-06-23 13:41:24 -07:00
platform Replace module_init with equivalent device_initcall in non modules. 2015-07-02 10:30:48 -07:00
power Merge branch 'x86-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-06-22 17:59:09 -07:00
purgatory Merge branches 'x86-build-for-linus', 'x86-cleanups-for-linus' and 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-12-10 12:35:46 -08:00
realmode Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-02-16 14:58:12 -08:00
tools x86, build: replace Perl script with Shell script 2015-01-26 13:37:18 -08:00
um x86/asm/tsc: Remove rdtsc_barrier() 2015-07-06 15:23:30 +02:00
video
xen x86/asm/tsc, x86/paravirt: Remove read_tsc() and read_tscp() paravirt hooks 2015-07-06 15:23:26 +02:00
.gitignore
Kbuild x86/asm/entry, x86/vdso: Move the vDSO code to arch/x86/entry/vdso/ 2015-06-03 18:51:37 +02:00
Kconfig x86: opt into HAVE_COPY_THREAD_TLS, for both 32-bit and 64-bit 2015-06-30 19:45:01 -07:00
Kconfig.cpu
Kconfig.debug Merge branch 'x86-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-06-22 17:59:09 -07:00
Makefile x86/asm/entry: Move the arch/x86/syscalls/ definitions to arch/x86/entry/syscalls/ 2015-06-04 07:37:37 +02:00
Makefile_32.cpu
Makefile.um kbuild: use relative path more to include Makefile 2015-04-02 16:42:08 +02:00