diff options
| author | Lukas Auer | 2019-01-04 01:37:32 +0100 |
|---|---|---|
| committer | Andes | 2019-01-15 09:36:31 +0800 |
| commit | cbb860f2c89c05c4c1d571f61bb76650db489d7d (patch) | |
| tree | 419f667093fc4c6e353fc4ce06e27a69693dd6fb /examples/standalone | |
| parent | 3c37278ff18577b711b14a1c2fcec37daa959f0a (diff) | |
riscv: replace use of callee-saved register in standalone
Register x19 (s3) is a callee-saved register. It must not be used to
load and jump to exported functions without saving it beforehand.
Replace it with t0, a temporary and caller-saved register.
Change the code comment to reflect this and fix it to correctly list gp
as the register with the pointer to global data.
Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
Diffstat (limited to 'examples/standalone')
| -rw-r--r-- | examples/standalone/stubs.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/examples/standalone/stubs.c b/examples/standalone/stubs.c index fadde669fa9..f37d209da6d 100644 --- a/examples/standalone/stubs.c +++ b/examples/standalone/stubs.c @@ -174,16 +174,16 @@ gd_t *global_data; : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "$r16"); #elif defined(CONFIG_RISCV) /* - * t7 holds the pointer to the global_data. gp is call clobbered. + * gp holds the pointer to the global_data. t0 is call clobbered. */ #define EXPORT_FUNC(f, a, x, ...) \ asm volatile ( \ " .globl " #x "\n" \ #x ":\n" \ -" lw x19, %0(gp)\n" \ -" lw x19, %1(x19)\n" \ -" jr x19\n" \ - : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "x19"); +" lw t0, %0(gp)\n" \ +" lw t0, %1(t0)\n" \ +" jr t0\n" \ + : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "t0"); #elif defined(CONFIG_ARC) /* * r25 holds the pointer to the global_data. r10 is call clobbered. |