Unverified Commit 6c58f25e authored by Nathan Huckleberry's avatar Nathan Huckleberry Committed by Palmer Dabbelt
Browse files

riscv/atomic: Fix sign extension for RV64I

The argument passed to cmpxchg is not guaranteed to be sign
extended, but lr.w sign extends on RV64I. This makes cmpxchg
fail on clang built kernels when __old is negative.

To fix this, we just cast __old to long which sign extends on
RV64I. With this fix, clang built RISC-V kernels now boot.

Link: https://github.com/ClangBuiltLinux/linux/issues/867

Signed-off-by: default avatarNathan Huckleberry <nhuck@google.com>
Signed-off-by: default avatarPalmer Dabbelt <palmerdabbelt@google.com>
parent cd16ed33
......@@ -179,7 +179,7 @@
" bnez %1, 0b\n" \
"1:\n" \
: "=&r" (__ret), "=&r" (__rc), "+A" (*__ptr) \
: "rJ" (__old), "rJ" (__new) \
: "rJ" ((long)__old), "rJ" (__new) \
: "memory"); \
break; \
case 8: \
......@@ -224,7 +224,7 @@
RISCV_ACQUIRE_BARRIER \
"1:\n" \
: "=&r" (__ret), "=&r" (__rc), "+A" (*__ptr) \
: "rJ" (__old), "rJ" (__new) \
: "rJ" ((long)__old), "rJ" (__new) \
: "memory"); \
break; \
case 8: \
......@@ -270,7 +270,7 @@
" bnez %1, 0b\n" \
"1:\n" \
: "=&r" (__ret), "=&r" (__rc), "+A" (*__ptr) \
: "rJ" (__old), "rJ" (__new) \
: "rJ" ((long)__old), "rJ" (__new) \
: "memory"); \
break; \
case 8: \
......@@ -316,7 +316,7 @@
" fence rw, rw\n" \
"1:\n" \
: "=&r" (__ret), "=&r" (__rc), "+A" (*__ptr) \
: "rJ" (__old), "rJ" (__new) \
: "rJ" ((long)__old), "rJ" (__new) \
: "memory"); \
break; \
case 8: \
......
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