linux_dsm_epyc7002/arch
Björn Töpel fe121ee531 bpf, riscv: clear target register high 32-bits for and/or/xor on ALU32
When using 32-bit subregisters (ALU32), the RISC-V JIT would not clear
the high 32-bits of the target register and therefore generate
incorrect code.

E.g., in the following code:

  $ cat test.c
  unsigned int f(unsigned long long a,
  	       unsigned int b)
  {
  	return (unsigned int)a & b;
  }

  $ clang-9 -target bpf -O2 -emit-llvm -S test.c -o - | \
  	llc-9 -mattr=+alu32 -mcpu=v3
  	.text
  	.file	"test.c"
  	.globl	f
  	.p2align	3
  	.type	f,@function
  f:
  	r0 = r1
  	w0 &= w2
  	exit
  .Lfunc_end0:
  	.size	f, .Lfunc_end0-f

The JIT would not clear the high 32-bits of r0 after the
and-operation, which in this case might give an incorrect return
value.

After this patch, that is not the case, and the upper 32-bits are
cleared.

Reported-by: Jiong Wang <jiong.wang@netronome.com>
Fixes: 2353ecc6f9 ("bpf, riscv: add BPF JIT for RV64G")
Signed-off-by: Björn Töpel <bjorn.topel@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-05-23 15:53:55 +02:00
..
alpha alpha: move arch/alpha/defconfig to arch/alpha/configs/defconfig 2019-05-18 11:49:55 +09:00
arc asm-generic: kill <asm/segment.h> and improve nommu generic uaccess helpers 2019-05-16 11:26:37 -07:00
arm Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-05-19 11:11:20 -07:00
arm64 Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-05-19 10:58:45 -07:00
c6x asm-generic: kill <asm/segment.h> and improve nommu generic uaccess helpers 2019-05-16 11:26:37 -07:00
csky arch: remove dangling asm-generic wrappers 2019-05-18 11:49:52 +09:00
h8300 arch: remove dangling asm-generic wrappers 2019-05-18 11:49:52 +09:00
hexagon asm-generic: kill <asm/segment.h> and improve nommu generic uaccess helpers 2019-05-16 11:26:37 -07:00
ia64 ia64: require -Wl,--hash-style=sysv 2019-05-18 11:29:01 +09:00
m68k Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-05-17 09:46:31 -07:00
microblaze Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-05-17 09:46:31 -07:00
mips Kbuild updates for v5.2 (2nd) 2019-05-19 11:53:58 -07:00
nds32 arch: remove dangling asm-generic wrappers 2019-05-18 11:49:52 +09:00
nios2 asm-generic: kill <asm/segment.h> and improve nommu generic uaccess helpers 2019-05-16 11:26:37 -07:00
openrisc asm-generic: kill <asm/segment.h> and improve nommu generic uaccess helpers 2019-05-16 11:26:37 -07:00
parisc Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-05-17 09:46:31 -07:00
powerpc Merge branch 'akpm' (patches from Andrew) 2019-05-19 12:15:32 -07:00
riscv bpf, riscv: clear target register high 32-bits for and/or/xor on ALU32 2019-05-23 15:53:55 +02:00
s390 * ARM: support for SVE and Pointer Authentication in guests, PMU improvements 2019-05-17 10:33:30 -07:00
sh treewide: prefix header search paths with $(srctree)/ 2019-05-18 11:49:57 +09:00
sparc Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-05-17 09:46:31 -07:00
um Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-05-19 10:23:24 -07:00
unicore32 Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-05-19 10:23:24 -07:00
x86 Kbuild updates for v5.2 (2nd) 2019-05-19 11:53:58 -07:00
xtensa treewide: prefix header search paths with $(srctree)/ 2019-05-18 11:49:57 +09:00
.gitignore
Kconfig Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-05-16 11:00:20 -07:00