authorgravatar for alex@alexrp.comAlex Rønne Petersen <alex@alexrp.com> 2024-11-12 18:06:42+01:00
committergravatar for alex@alexrp.comAlex Rønne Petersen <alex@alexrp.com> 2024-12-11 00:10:17+01:00
log43b6bd42434cdc71e3405b4d5c3a36f6ff76ed01
tree0cbf136c79108ff0434f5739e4cb590d5720e535
parent8af82621d75f9f0d96ebf734f5ea862d06a5f1fa
signaturebadge-check Signed by SSH key SHA256:7B/LJ7bpR1eX8aCXSr4mtd5M45VMPKcx9zY8e95b5QM

start: Zero the link and frame pointer registers on all architectures.

1 files changed, 22 insertions(+), 5 deletions(-)

lib/std/start.zig+22-5
...@@ -279,8 +279,10 @@ fn _start() callconv(.naked) noreturn {...@@ -279,8 +279,10 @@ fn _start() callconv(.naked) noreturn {
279 ,279 ,
280 .arm, .armeb, .thumb, .thumbeb =>280 .arm, .armeb, .thumb, .thumbeb =>
281 // Note that this code must work for Thumb-1.281 // Note that this code must work for Thumb-1.
282 // r7 = FP (local), r11 = FP (unwind)
282 \\ movs v1, #0283 \\ movs v1, #0
283 \\ mov fp, v1284 \\ mov r7, v1
285 \\ mov r11, v1
284 \\ mov lr, v1286 \\ mov lr, v1
285 \\ mov a1, sp287 \\ mov a1, sp
286 \\ subs v1, #16288 \\ subs v1, #16
...@@ -290,20 +292,23 @@ fn _start() callconv(.naked) noreturn {...@@ -290,20 +292,23 @@ fn _start() callconv(.naked) noreturn {
290 ,292 ,
291 .csky =>293 .csky =>
292 // The CSKY ABI assumes that `gb` is set to the address of the GOT in order for294 // The CSKY ABI assumes that `gb` is set to the address of the GOT in order for
293 // position-independent code to work. We depend on this in `std.os.linux.start_pie`295 // position-independent code to work. We depend on this in `std.os.linux.pie` to locate
294 // to locate `_DYNAMIC` as well.296 // `_DYNAMIC` as well.
297 // r8 = FP
295 \\ grs t0, 1f298 \\ grs t0, 1f
296 \\ 1:299 \\ 1:
297 \\ lrw gb, 1b@GOTPC300 \\ lrw gb, 1b@GOTPC
298 \\ addu gb, t0301 \\ addu gb, t0
302 \\ movi r8, 0
299 \\ movi lr, 0303 \\ movi lr, 0
300 \\ mov a0, sp304 \\ mov a0, sp
301 \\ andi sp, sp, -8305 \\ andi sp, sp, -8
302 \\ jmpi %[posixCallMainAndExit]306 \\ jmpi %[posixCallMainAndExit]
303 ,307 ,
304 .hexagon =>308 .hexagon =>
305 // r29 = SP, r30 = FP309 // r29 = SP, r30 = FP, r31 = LR
306 \\ r30 = #0310 \\ r30 = #0
311 \\ r31 = #0
307 \\ r0 = r29312 \\ r0 = r29
308 \\ r29 = and(r29, #-16)313 \\ r29 = and(r29, #-16)
309 \\ memw(r29 + #-8) = r29314 \\ memw(r29 + #-8) = r29
...@@ -312,12 +317,13 @@ fn _start() callconv(.naked) noreturn {...@@ -312,12 +317,13 @@ fn _start() callconv(.naked) noreturn {
312 ,317 ,
313 .loongarch32, .loongarch64 =>318 .loongarch32, .loongarch64 =>
314 \\ move $fp, $zero319 \\ move $fp, $zero
320 \\ move $ra, $zero
315 \\ move $a0, $sp321 \\ move $a0, $sp
316 \\ bstrins.d $sp, $zero, 3, 0322 \\ bstrins.d $sp, $zero, 3, 0
317 \\ b %[posixCallMainAndExit]323 \\ b %[posixCallMainAndExit]
318 ,324 ,
319 .riscv32, .riscv64 =>325 .riscv32, .riscv64 =>
320 \\ li s0, 0326 \\ li fp, 0
321 \\ li ra, 0327 \\ li ra, 0
322 \\ mv a0, sp328 \\ mv a0, sp
323 \\ andi sp, sp, -16329 \\ andi sp, sp, -16
...@@ -371,28 +377,35 @@ fn _start() callconv(.naked) noreturn {...@@ -371,28 +377,35 @@ fn _start() callconv(.naked) noreturn {
371 ,377 ,
372 .powerpc, .powerpcle =>378 .powerpc, .powerpcle =>
373 // Set up the initial stack frame, and clear the back chain pointer.379 // Set up the initial stack frame, and clear the back chain pointer.
380 // r1 = SP, r31 = FP
374 \\ mr 3, 1381 \\ mr 3, 1
375 \\ clrrwi 1, 1, 4382 \\ clrrwi 1, 1, 4
376 \\ li 0, 0383 \\ li 0, 0
377 \\ stwu 1, -16(1)384 \\ stwu 1, -16(1)
378 \\ stw 0, 0(1)385 \\ stw 0, 0(1)
386 \\ li 31, 0
379 \\ mtlr 0387 \\ mtlr 0
380 \\ b %[posixCallMainAndExit]388 \\ b %[posixCallMainAndExit]
381 ,389 ,
382 .powerpc64, .powerpc64le =>390 .powerpc64, .powerpc64le =>
383 // Set up the ToC and initial stack frame, and clear the back chain pointer.391 // Set up the ToC and initial stack frame, and clear the back chain pointer.
392 // r1 = SP, r2 = ToC, r31 = FP
384 \\ addis 2, 12, .TOC. - %[_start]@ha393 \\ addis 2, 12, .TOC. - %[_start]@ha
385 \\ addi 2, 2, .TOC. - %[_start]@l394 \\ addi 2, 2, .TOC. - %[_start]@l
386 \\ mr 3, 1395 \\ mr 3, 1
387 \\ clrrdi 1, 1, 4396 \\ clrrdi 1, 1, 4
388 \\ li 0, 0397 \\ li 0, 0
389 \\ stdu 0, -32(1)398 \\ stdu 0, -32(1)
399 \\ li 31, 0
390 \\ mtlr 0400 \\ mtlr 0
391 \\ b %[posixCallMainAndExit]401 \\ b %[posixCallMainAndExit]
392 \\ nop402 \\ nop
393 ,403 ,
394 .s390x =>404 .s390x =>
395 // Set up the stack frame (register save area and cleared back-chain slot).405 // Set up the stack frame (register save area and cleared back-chain slot).
406 // r11 = FP, r14 = LR, r15 = SP
407 \\ lghi %%r11, 0
408 \\ lghi %%r14, 0
396 \\ lgr %%r2, %%r15409 \\ lgr %%r2, %%r15
397 \\ lghi %%r0, -16410 \\ lghi %%r0, -16
398 \\ ngr %%r15, %%r0411 \\ ngr %%r15, %%r0
...@@ -403,7 +416,9 @@ fn _start() callconv(.naked) noreturn {...@@ -403,7 +416,9 @@ fn _start() callconv(.naked) noreturn {
403 ,416 ,
404 .sparc =>417 .sparc =>
405 // argc is stored after a register window (16 registers * 4 bytes).418 // argc is stored after a register window (16 registers * 4 bytes).
419 // i7 = LR
406 \\ mov %%g0, %%fp420 \\ mov %%g0, %%fp
421 \\ mov %%g0, %%i7
407 \\ add %%sp, 64, %%o0422 \\ add %%sp, 64, %%o0
408 \\ and %%sp, -8, %%sp423 \\ and %%sp, -8, %%sp
409 \\ ba,a %[posixCallMainAndExit]424 \\ ba,a %[posixCallMainAndExit]
...@@ -411,7 +426,9 @@ fn _start() callconv(.naked) noreturn {...@@ -411,7 +426,9 @@ fn _start() callconv(.naked) noreturn {
411 .sparc64 =>426 .sparc64 =>
412 // argc is stored after a register window (16 registers * 8 bytes) plus the stack bias427 // argc is stored after a register window (16 registers * 8 bytes) plus the stack bias
413 // (2047 bytes).428 // (2047 bytes).
429 // i7 = LR
414 \\ mov %%g0, %%fp430 \\ mov %%g0, %%fp
431 \\ mov %%g0, %%i7
415 \\ add %%sp, 2175, %%o0432 \\ add %%sp, 2175, %%o0
416 \\ add %%sp, 2047, %%sp433 \\ add %%sp, 2047, %%sp
417 \\ and %%sp, -16, %%sp434 \\ and %%sp, -16, %%sp