Revision 61f01dd941ba9e06d2bf05994450ecc3d61b6b8b authored by Andy Lutomirski on 26 April 2015, 23:47:59 UTC, committed by Linus Torvalds on 27 April 2015, 00:57:38 UTC
AMD CPUs don't reinitialize the SS descriptor on SYSRET, so SYSRET with
SS == 0 results in an invalid usermode state in which SS is apparently
equal to __USER_DS but causes #SS if used.

Work around the issue by setting SS to __KERNEL_DS __switch_to, thus
ensuring that SYSRET never happens with SS set to NULL.

This was exposed by a recent vDSO cleanup.

Fixes: e7d6eefaaa44 x86/vdso32/syscall.S: Do not load __USER32_DS to %ss
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 1190944
History
File Mode Size
Makefile -rw-r--r-- 283 bytes
asm-offsets.c -rw-r--r-- 3.6 KB
c6x_ksyms.c -rw-r--r-- 2.0 KB
devicetree.c -rw-r--r-- 493 bytes
dma.c -rw-r--r-- 3.6 KB
entry.S -rw-r--r-- 15.6 KB
head.S -rw-r--r-- 1.7 KB
irq.c -rw-r--r-- 3.1 KB
module.c -rw-r--r-- 3.2 KB
process.c -rw-r--r-- 3.3 KB
ptrace.c -rw-r--r-- 4.1 KB
setup.c -rw-r--r-- 11.2 KB
signal.c -rw-r--r-- 8.1 KB
soc.c -rw-r--r-- 2.0 KB
switch_to.S -rw-r--r-- 1.6 KB
sys_c6x.c -rw-r--r-- 1.9 KB
time.c -rw-r--r-- 1.5 KB
traps.c -rw-r--r-- 14.5 KB
vectors.S -rw-r--r-- 1.7 KB
vmlinux.lds.S -rw-r--r-- 2.4 KB

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