diff options
Diffstat (limited to 'packages/gcc/11.4.0/0025-aarch64-Put-LR-save-probe-in-first-16-bytes.patch')
| -rw-r--r-- | packages/gcc/11.4.0/0025-aarch64-Put-LR-save-probe-in-first-16-bytes.patch | 263 |
1 files changed, 0 insertions, 263 deletions
diff --git a/packages/gcc/11.4.0/0025-aarch64-Put-LR-save-probe-in-first-16-bytes.patch b/packages/gcc/11.4.0/0025-aarch64-Put-LR-save-probe-in-first-16-bytes.patch deleted file mode 100644 index ca10742e..00000000 --- a/packages/gcc/11.4.0/0025-aarch64-Put-LR-save-probe-in-first-16-bytes.patch +++ /dev/null @@ -1,263 +0,0 @@ -From 174a9747491e591ef2abb3e20a0332303f11003a Mon Sep 17 00:00:00 2001 -From: Richard Sandiford <richard.sandiford@arm.com> -Date: Tue, 12 Sep 2023 16:19:49 +0100 -Subject: [PATCH 25/29] aarch64: Put LR save probe in first 16 bytes - --fstack-clash-protection uses the save of LR as a probe for the next -allocation. The next allocation could be: - -* another part of the static frame, e.g. when allocating SVE save slots - or outgoing arguments - -* an alloca in the same function - -* an allocation made by a callee function - -However, when -fomit-frame-pointer is used, the LR save slot is placed -above the other GPR save slots. It could therefore be up to 80 bytes -above the base of the GPR save area (which is also the hard fp address). - -aarch64_allocate_and_probe_stack_space took this into account when -deciding how much subsequent space could be allocated without needing -a probe. However, it interacted badly with: - - /* If doing a small final adjustment, we always probe at offset 0. - This is done to avoid issues when LR is not at position 0 or when - the final adjustment is smaller than the probing offset. */ - else if (final_adjustment_p && rounded_size == 0) - residual_probe_offset = 0; - -which forces any allocation that is smaller than the guard page size -to be probed at offset 0 rather than the usual offset 1024. It was -therefore possible to construct cases in which we had: - -* a probe using LR at SP + 80 bytes (or some other value >= 16) -* an allocation of the guard page size - 16 bytes -* a probe at SP + 0 - -which allocates guard page size + 64 consecutive unprobed bytes. - -This patch requires the LR probe to be in the first 16 bytes of the -save area when stack clash protection is active. Doing it -unconditionally would cause code-quality regressions, but a later -patch deals with that. - -The new comment doesn't say that the probe register is required -to be LR, since a later patch removes that restriction. - -gcc/ - * config/aarch64/aarch64.c (aarch64_layout_frame): Ensure that - the LR save slot is in the first 16 bytes of the register save area. - (aarch64_allocate_and_probe_stack_space): Remove workaround for - when LR was not in the first 16 bytes. - -gcc/testsuite/ - * gcc.target/aarch64/stack-check-prologue-18.c: New test. ---- - gcc/config/aarch64/aarch64.c | 61 ++++------- - .../aarch64/stack-check-prologue-18.c | 100 ++++++++++++++++++ - 2 files changed, 123 insertions(+), 38 deletions(-) - create mode 100644 gcc/testsuite/gcc.target/aarch64/stack-check-prologue-18.c - -diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c -index bfd248761951..3f2b10de987d 100644 ---- a/gcc/config/aarch64/aarch64.c -+++ b/gcc/config/aarch64/aarch64.c -@@ -7532,26 +7532,34 @@ aarch64_layout_frame (void) - bool saves_below_hard_fp_p - = maybe_ne (frame.below_hard_fp_saved_regs_size, 0); - frame.bytes_below_hard_fp = offset; -+ -+ auto allocate_gpr_slot = [&](unsigned int regno) -+ { -+ frame.reg_offset[regno] = offset; -+ if (frame.wb_candidate1 == INVALID_REGNUM) -+ frame.wb_candidate1 = regno; -+ else if (frame.wb_candidate2 == INVALID_REGNUM) -+ frame.wb_candidate2 = regno; -+ offset += UNITS_PER_WORD; -+ }; -+ - if (frame.emit_frame_chain) - { - /* FP and LR are placed in the linkage record. */ -- frame.reg_offset[R29_REGNUM] = offset; -- frame.wb_candidate1 = R29_REGNUM; -- frame.reg_offset[R30_REGNUM] = offset + UNITS_PER_WORD; -- frame.wb_candidate2 = R30_REGNUM; -- offset += 2 * UNITS_PER_WORD; -+ allocate_gpr_slot (R29_REGNUM); -+ allocate_gpr_slot (R30_REGNUM); - } -+ else if (flag_stack_clash_protection -+ && known_eq (frame.reg_offset[R30_REGNUM], SLOT_REQUIRED)) -+ /* Put the LR save slot first, since it makes a good choice of probe -+ for stack clash purposes. The idea is that the link register usually -+ has to be saved before a call anyway, and so we lose little by -+ stopping it from being individually shrink-wrapped. */ -+ allocate_gpr_slot (R30_REGNUM); - - for (regno = R0_REGNUM; regno <= R30_REGNUM; regno++) - if (known_eq (frame.reg_offset[regno], SLOT_REQUIRED)) -- { -- frame.reg_offset[regno] = offset; -- if (frame.wb_candidate1 == INVALID_REGNUM) -- frame.wb_candidate1 = regno; -- else if (frame.wb_candidate2 == INVALID_REGNUM) -- frame.wb_candidate2 = regno; -- offset += UNITS_PER_WORD; -- } -+ allocate_gpr_slot (regno); - - poly_int64 max_int_offset = offset; - offset = aligned_upper_bound (offset, STACK_BOUNDARY / BITS_PER_UNIT); -@@ -8570,29 +8578,6 @@ aarch64_allocate_and_probe_stack_space (rtx temp1, rtx temp2, - = (final_adjustment_p - ? guard_used_by_caller + byte_sp_alignment - : guard_size - guard_used_by_caller); -- /* When doing the final adjustment for the outgoing arguments, take into -- account any unprobed space there is above the current SP. There are -- two cases: -- -- - When saving SVE registers below the hard frame pointer, we force -- the lowest save to take place in the prologue before doing the final -- adjustment (i.e. we don't allow the save to be shrink-wrapped). -- This acts as a probe at SP, so there is no unprobed space. -- -- - When there are no SVE register saves, we use the store of the link -- register as a probe. We can't assume that LR was saved at position 0 -- though, so treat any space below it as unprobed. */ -- if (final_adjustment_p -- && known_eq (frame.below_hard_fp_saved_regs_size, 0)) -- { -- poly_int64 lr_offset = (frame.reg_offset[LR_REGNUM] -- - frame.bytes_below_saved_regs); -- if (known_ge (lr_offset, 0)) -- min_probe_threshold -= lr_offset.to_constant (); -- else -- gcc_assert (!flag_stack_clash_protection || known_eq (poly_size, 0)); -- } -- - poly_int64 frame_size = frame.frame_size; - - /* We should always have a positive probe threshold. */ -@@ -8772,8 +8757,8 @@ aarch64_allocate_and_probe_stack_space (rtx temp1, rtx temp2, - if (final_adjustment_p && rounded_size != 0) - min_probe_threshold = 0; - /* If doing a small final adjustment, we always probe at offset 0. -- This is done to avoid issues when LR is not at position 0 or when -- the final adjustment is smaller than the probing offset. */ -+ This is done to avoid issues when the final adjustment is smaller -+ than the probing offset. */ - else if (final_adjustment_p && rounded_size == 0) - residual_probe_offset = 0; - -diff --git a/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-18.c b/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-18.c -new file mode 100644 -index 000000000000..82447d20fff5 ---- /dev/null -+++ b/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-18.c -@@ -0,0 +1,100 @@ -+/* { dg-options "-O2 -fstack-clash-protection -fomit-frame-pointer --param stack-clash-protection-guard-size=12" } */ -+/* { dg-final { check-function-bodies "**" "" } } */ -+ -+void f(int, ...); -+void g(); -+ -+/* -+** test1: -+** ... -+** str x30, \[sp\] -+** sub sp, sp, #4064 -+** str xzr, \[sp\] -+** cbnz w0, .* -+** bl g -+** ... -+** str x26, \[sp, #?4128\] -+** ... -+*/ -+int test1(int z) { -+ __uint128_t x = 0; -+ int y[0x400]; -+ if (z) -+ { -+ asm volatile ("" ::: -+ "x19", "x20", "x21", "x22", "x23", "x24", "x25", "x26"); -+ f(0, 0, 0, 0, 0, 0, 0, &y, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x); -+ } -+ g(); -+ return 1; -+} -+ -+/* -+** test2: -+** ... -+** str x30, \[sp\] -+** sub sp, sp, #1040 -+** str xzr, \[sp\] -+** cbnz w0, .* -+** bl g -+** ... -+*/ -+int test2(int z) { -+ __uint128_t x = 0; -+ int y[0x400]; -+ if (z) -+ { -+ asm volatile ("" ::: -+ "x19", "x20", "x21", "x22", "x23", "x24", "x25", "x26"); -+ f(0, 0, 0, 0, 0, 0, 0, &y, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x); -+ } -+ g(); -+ return 1; -+} -+ -+/* -+** test3: -+** ... -+** str x30, \[sp\] -+** sub sp, sp, #1024 -+** cbnz w0, .* -+** bl g -+** ... -+*/ -+int test3(int z) { -+ __uint128_t x = 0; -+ int y[0x400]; -+ if (z) -+ { -+ asm volatile ("" ::: -+ "x19", "x20", "x21", "x22", "x23", "x24", "x25", "x26"); -+ f(0, 0, 0, 0, 0, 0, 0, &y, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, -+ x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x); -+ } -+ g(); -+ return 1; -+} --- -2.42.0 - |