diff options
Diffstat (limited to 'libgcc')
| -rw-r--r-- | libgcc/ChangeLog | 11 | ||||
| -rw-r--r-- | libgcc/Makefile.in | 2 | ||||
| -rw-r--r-- | libgcc/config/aarch64/linux-unwind.h | 108 |
3 files changed, 118 insertions, 3 deletions
diff --git a/libgcc/ChangeLog b/libgcc/ChangeLog index f05492e..055e7ca 100644 --- a/libgcc/ChangeLog +++ b/libgcc/ChangeLog @@ -1,3 +1,14 @@ +2025-07-17 Richard Sandiford <richard.sandiford@arm.com> + Yury Khrustalev <yury.khrustalev@arm.com> + + * config/aarch64/linux-unwind.h (aarch64_fallback_frame_state): + If a signal was raised while there was an uncommitted lazy save, + commit the save as part of the unwind process. + +2025-07-16 John Ericson <git@JohnEricson.me> + + * Makefile.in: Delete dead `MACHMODE_H` variable + 2025-07-10 Jan Dubiec <jdx@o2.pl> PR target/116363 diff --git a/libgcc/Makefile.in b/libgcc/Makefile.in index 0719fd0..f7b48dc 100644 --- a/libgcc/Makefile.in +++ b/libgcc/Makefile.in @@ -193,7 +193,6 @@ AWK = @AWK@ GCC_FOR_TARGET = $(CC) LIPO = @LIPO@ LIPO_FOR_TARGET = $(LIPO) -MACHMODE_H = machmode.h mode-classes.def insn-modes.h NM = @NM@ NM_FOR_TARGET = $(NM) RANLIB_FOR_TARGET = $(RANLIB) @@ -220,7 +219,6 @@ export INSTALL_DATA export LIB1ASMSRC export LIBGCC2_CFLAGS export LIPO_FOR_TARGET -export MACHMODE_H export NM_FOR_TARGET export STRIP_FOR_TARGET export RANLIB_FOR_TARGET diff --git a/libgcc/config/aarch64/linux-unwind.h b/libgcc/config/aarch64/linux-unwind.h index e41ca6a..f5b73a0 100644 --- a/libgcc/config/aarch64/linux-unwind.h +++ b/libgcc/config/aarch64/linux-unwind.h @@ -27,7 +27,7 @@ #include <signal.h> #include <sys/ucontext.h> - +#include <stdint.h> /* Since insns are always stored LE, on a BE system the opcodes will be loaded byte-reversed. Therefore, define two sets of opcodes, @@ -43,6 +43,22 @@ #define MD_FALLBACK_FRAME_STATE_FOR aarch64_fallback_frame_state +#ifndef FPSIMD_MAGIC +#define FPSIMD_MAGIC 0x46508001 +#endif + +#ifndef TPIDR2_MAGIC +#define TPIDR2_MAGIC 0x54504902 +#endif + +#ifndef ZA_MAGIC +#define ZA_MAGIC 0x54366345 +#endif + +#ifndef EXTRA_MAGIC +#define EXTRA_MAGIC 0x45585401 +#endif + static _Unwind_Reason_Code aarch64_fallback_frame_state (struct _Unwind_Context *context, _Unwind_FrameState * fs) @@ -58,6 +74,21 @@ aarch64_fallback_frame_state (struct _Unwind_Context *context, ucontext_t uc; }; + struct tpidr2_block + { + uint64_t za_save_buffer; + uint16_t num_za_save_slices; + uint8_t reserved[6]; + }; + + struct za_block + { + struct _aarch64_ctx head; + uint16_t vl; + uint16_t reserved[3]; + uint64_t data; + }; + struct rt_sigframe *rt_; _Unwind_Ptr new_cfa; unsigned *pc = context->ra; @@ -103,11 +134,15 @@ aarch64_fallback_frame_state (struct _Unwind_Context *context, field can be used to skip over unrecognized context extensions. The end of the context sequence is marked by a context with magic 0 or size 0. */ + struct tpidr2_block *tpidr2 = 0; + struct za_block *za_ctx = 0; + for (extension_marker = (struct _aarch64_ctx *) &sc->__reserved; extension_marker->magic; extension_marker = (struct _aarch64_ctx *) ((unsigned char *) extension_marker + extension_marker->size)) { + restart: if (extension_marker->magic == FPSIMD_MAGIC) { struct fpsimd_context *ctx = @@ -139,12 +174,83 @@ aarch64_fallback_frame_state (struct _Unwind_Context *context, fs->regs.reg[AARCH64_DWARF_V0 + i].loc.offset = offset; } } + else if (extension_marker->magic == TPIDR2_MAGIC) + { + /* A TPIDR2 context. + + All the casting is to support big-endian ILP32. We could read + directly into TPIDR2 otherwise. */ + struct { struct _aarch64_ctx h; uint64_t tpidr2; } *ctx + = (void *)extension_marker; +#if defined (__ILP32__) + tpidr2 = (struct tpidr2_block *) (uintptr_t) ctx->tpidr2; +#else + tpidr2 = (struct tpidr2_block *) ctx->tpidr2; +#endif + } + else if (extension_marker->magic == ZA_MAGIC) + /* A ZA context. We interpret this later. */ + za_ctx = (void *)extension_marker; + else if (extension_marker->magic == EXTRA_MAGIC) + { + /* Extra context. The ABI guarantees that the next _aarch64_ctx + in the current list will be the zero terminator, so we can simply + switch to the new list and continue from there. The new list is + also zero-terminated. + + As above, the casting is to support big-endian ILP32. */ + struct { struct _aarch64_ctx h; uint64_t next; } *ctx + = (void *)extension_marker; +#if defined (__ILP32__) + extension_marker = (struct _aarch64_ctx *) (uintptr_t) ctx->next; +#else + extension_marker = (struct _aarch64_ctx *) ctx->next; +#endif + goto restart; + } else { /* There is context provided that we do not recognize! */ } } + /* Signal handlers are entered with ZA in the off state (TPIDR2_ELO==0 and + PSTATE.ZA==0). The normal process when transitioning from ZA being + dormant to ZA being off is to commit the lazy save; see the AAPCS64 + for details. However, this is not done when entering a signal handler. + Instead, linux saves the old contents of ZA and TPIDR2_EL0 to the + sigcontext without interpreting them further. + + Therefore, if a signal handler throws an exception to code outside the + signal handler, the unwinder must commit the lazy save after the fact. + Committing a lazy save means: + + (1) Storing the contents of ZA into the buffer provided by TPIDR2_EL0. + (2) Setting TPIDR2_EL0 to zero. + (3) Turning ZA off. + + (2) and (3) have already been done by the call to __libgcc_arm_za_disable. + (1) involves copying data from the ZA sigcontext entry to the + corresponding lazy save buffer. */ + if (tpidr2 && za_ctx && tpidr2->za_save_buffer) + { + /* There is a 16-bit vector length (measured in bytes) at ZA_CTX + 8. + The data itself starts at ZA_CTX + 16. + As above, the casting is to support big-endian ILP32. */ + uint16_t vl = za_ctx->vl; +#if defined (__ILP32__) + void *save_buffer = (void *) (uintptr_t) tpidr2->za_save_buffer; + const void *za_buffer = (void *) (uintptr_t) &za_ctx->data; +#else + void *save_buffer = (void *) tpidr2->za_save_buffer; + const void *za_buffer = (void *) &za_ctx->data; +#endif + uint64_t num_slices = tpidr2->num_za_save_slices; + if (num_slices > vl) + num_slices = vl; + memcpy (save_buffer, za_buffer, num_slices * vl); + } + fs->regs.how[31] = REG_SAVED_OFFSET; fs->regs.reg[31].loc.offset = (_Unwind_Ptr) & (sc->sp) - new_cfa; |