mirror of
https://github.com/Fishwaldo/Star64_linux.git
synced 2025-03-16 12:14:06 +00:00
powerpc/dcr: Use cmplwi instead of 3-argument cmpli
[ Upstream commit fef071be57
]
In dcr-low.S we use cmpli with three arguments, instead of four
arguments as defined in the ISA:
cmpli cr0,r3,1024
This appears to be a PPC440-ism, looking at the "PPC440x5 CPU Core
User’s Manual" it shows cmpli having no L field, but implied to be 0 due
to the core being 32-bit. It mentions that the ISA defines four
arguments and recommends using cmplwi.
It also corresponds to the old POWER instruction set, which had no L
field there, a reserved bit instead.
dcr-low.S is only built 32-bit, because it is only built when
DCR_NATIVE=y, which is only selected by 40x and 44x. Looking at the
generated code (with gcc/gas) we see cmplwi as expected.
Although gas is happy with the 3-argument version when building for
32-bit, the LLVM assembler is not and errors out with:
arch/powerpc/sysdev/dcr-low.S:27:10: error: invalid operand for instruction
cmpli 0,%r3,1024; ...
^
Switch to the cmplwi extended opcode, which avoids any confusion when
reading the ISA, fixes the issue with the LLVM assembler, and also means
the code could be built 64-bit in future (though that's very unlikely).
Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
BugLink: https://github.com/ClangBuiltLinux/linux/issues/1419
Link: https://lore.kernel.org/r/20211014024424.528848-1-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
7ad91228b8
commit
f3be18c200
1 changed files with 1 additions and 1 deletions
|
@ -11,7 +11,7 @@
|
|||
#include <asm/export.h>
|
||||
|
||||
#define DCR_ACCESS_PROLOG(table) \
|
||||
cmpli cr0,r3,1024; \
|
||||
cmplwi cr0,r3,1024; \
|
||||
rlwinm r3,r3,4,18,27; \
|
||||
lis r5,table@h; \
|
||||
ori r5,r5,table@l; \
|
||||
|
|
Loading…
Add table
Reference in a new issue