linux_dsm_epyc7002/arch/x86
Ingo Molnar 2e85591a6c x86/fpu: Better document fpu__clear() state handling
So prior to this fix:

  c88d47480d ("x86/fpu: Always restore_xinit_state() when use_eager_cpu()")

we leaked FPU state across execve() boundaries on eagerfpu systems:

	$ /host/home/mingo/dump-xmm-regs-exec
	# XMM state before execve():
	XMM0 : 000000000000dede
	XMM1 : 000000000000dedf
	XMM2 : 000000000000dee0
	XMM3 : 000000000000dee1
	XMM4 : 000000000000dee2
	XMM5 : 000000000000dee3
	XMM6 : 000000000000dee4
	XMM7 : 000000000000dee5
	XMM8 : 000000000000dee6
	XMM9 : 000000000000dee7
	XMM10: 000000000000dee8
	XMM11: 000000000000dee9
	XMM12: 000000000000deea
	XMM13: 000000000000deeb
	XMM14: 000000000000deec
	XMM15: 000000000000deed

	# XMM state after execve(), in the new task context:
	XMM0 : 0000000000000000
	XMM1 : 2f2f2f2f2f2f2f2f
	XMM2 : 0000000000000000
	XMM3 : 0000000000000000
	XMM4 : 00000000000000ff
	XMM5 : 00000000ff000000
	XMM6 : 000000000000dee4
	XMM7 : 000000000000dee5
	XMM8 : 0000000000000000
	XMM9 : 0000000000000000
	XMM10: 0000000000000000
	XMM11: 0000000000000000
	XMM12: 0000000000000000
	XMM13: 000000000000deeb
	XMM14: 000000000000deec
	XMM15: 000000000000deed

Better explain what this function is supposed to do and why.

Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-19 15:48:02 +02:00
..
boot * Avoid garbage names in efivarfs due to buggy firmware by zero'ing 2015-05-06 08:30:24 +02:00
configs x86/build/defconfig: Enable USB_EHCI_TT_NEWSCHED=y 2015-02-19 02:21:14 +01:00
crypto x86/fpu, crypto x86/sha1_mb: Remove FPU internal headers from sha1_mb.c 2015-05-19 15:47:59 +02:00
ia32 x86/fpu: Rename save_xstate_sig() to copy_fpstate_to_sigframe() 2015-05-19 15:48:01 +02:00
include x86/fpu: Rename user_has_fpu() to fpregs_active() 2015-05-19 15:48:02 +02:00
kernel x86/fpu: Better document fpu__clear() state handling 2015-05-19 15:48:02 +02:00
kvm x86/fpu: Rename user_has_fpu() to fpregs_active() 2015-05-19 15:48:02 +02:00
lguest x86/fpu: Rename i387.h to fpu/api.h 2015-05-19 15:47:30 +02:00
lib x86/fpu: Rename i387.h to fpu/api.h 2015-05-19 15:47:30 +02:00
math-emu x86/fpu: Simplify fpstate_init_curr() usage 2015-05-19 15:47:51 +02:00
mm x86/fpu: Simplify FPU handling by embedding the fpstate in task_struct (again) 2015-05-19 15:47:49 +02:00
net x86: bpf_jit: fix FROM_BE16 and FROM_LE16/32 instructions 2015-05-12 23:13:08 -04:00
oprofile x86/asm/entry: Change all 'user_mode_vm()' calls to 'user_mode()' 2015-03-23 11:14:17 +01:00
pci x86/PCI/ACPI: Make all resources except [io 0xcf8-0xcff] available on PCI bus 2015-04-30 22:17:34 +02:00
platform TTY/Serial patches for 4.1-rc1 2015-04-21 09:33:10 -07:00
power x86/fpu: Move various internal function prototypes to fpu/internal.h 2015-05-19 15:47:48 +02:00
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
syscalls xen: features and fixes for 4.1-rc0 2015-04-16 14:01:03 -05:00
tools x86, build: replace Perl script with Shell script 2015-01-26 13:37:18 -08:00
um Merge branch 'exec_domain_rip_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/misc 2015-04-15 13:53:55 -07:00
vdso x86/vdso: Fix 'make bzImage' on older distros 2015-05-11 10:25:02 +02:00
video
xen x86/fpu: Simplify fpu__cpu_init() 2015-05-19 15:47:44 +02:00
.gitignore x86/build: Add arch/x86/purgatory/ make generated files to gitignore 2014-10-09 09:29:46 +02:00
Kbuild kexec: create a new config option CONFIG_KEXEC_FILE for new syscall 2014-08-29 16:28:16 -07:00
Kconfig Initial ACPI support for arm64: 2015-04-24 08:23:45 -07:00
Kconfig.cpu
Kconfig.debug x86, intel-mid: remove Intel MID specific serial support 2015-03-07 03:25:18 +01:00
Makefile kbuild: use relative path more to include Makefile 2015-04-02 16:42:08 +02:00
Makefile_32.cpu
Makefile.um kbuild: use relative path more to include Makefile 2015-04-02 16:42:08 +02:00