| author |  Alex Rønne Petersen <alex@alexrp.com> 2026-08-09 02:20:55+02:00 |
| committer | Alex Rønne Petersen <alex@alexrp.com> 2026-08-09 17:53:03+02:00 |
| log | d8426e69c34768fda27c47078aafdec1f20f020b |
| tree | b934d7853413a414c205a6a9724b90694ee77beb |
| parent | c65e90d741b7f6016f907c4d1fd8717ab19240d1 |
| signature |  Signed by SSH key SHA256:7B/LJ7bpR1eX8aCXSr4mtd5M45VMPKcx9zY8e95b5QM |
std.os.linux.powerpc: respect ABI backchain requirements in clone assembly
The ABI says that a stack frame always starts with the backchain slot and the LR
save slot. Actually respect that by storing the old stack pointer in the
backchain slot and storing r29 and r30 in the locals area instead.1 files changed, 5 insertions(+), 4 deletions(-)
lib- std
- os
- linux
lib/std/os/linux/powerpc.zig+5-4
| ... | ... | @@ -200,8 +200,9 @@ pub fn clone() callconv(.naked) u32 { |
| 200 | 200 | asm volatile ( |
| 201 | 201 | \\ # store non-volatile regs r29, r30 on stack in order to put our |
| 202 | 202 | \\ # start func and its arg there |
| 203 | \\ stwu 29, -16(1) | |
| 204 | \\ stw 30, 4(1) | |
| 203 | \\ stwu 1, -16(1) | |
| 204 | \\ stw 29, 8(1) | |
| 205 | \\ stw 30, 12(1) | |
| 205 | 206 | \\ |
| 206 | 207 | \\ # save r3 (func) into r29, and r6(arg) into r30 |
| 207 | 208 | \\ mr 29, 3 |
| ... | ... | @@ -234,8 +235,8 @@ pub fn clone() callconv(.naked) u32 { |
| 234 | 235 | \\ |
| 235 | 236 | \\ # if not 0, restore stack and return |
| 236 | 237 | \\ beq cr7, 2f |
| 237 | \\ lwz 29, 0(1) | |
| 238 | \\ lwz 30, 4(1) | |
| 238 | \\ lwz 29, 8(1) | |
| 239 | \\ lwz 30, 12(1) | |
| 239 | 240 | \\ addi 1, 1, 16 |
| 240 | 241 | \\ blr |
| 241 | 242 | \\ |