From 6f67973b4280cfd045e632a3340becd16e43b4b1 Mon Sep 17 00:00:00 2001 From: Yao Qi Date: Thu, 4 Aug 2016 11:37:57 +0100 Subject: [PATCH] Determine target description for native aarch64 I find the following test fail when I test native aarch64 gdb with arm program, (gdb) PASS: gdb.base/attach-pie-noexec.exp: attach set architecture arm^M warning: Selected architecture arm is not compatible with reported target architecture aarch64^M Architecture `arm' not recognized.^M The target architecture is set automatically (currently aarch64)^M (gdb) FAIL: gdb.base/attach-pie-noexec.exp: set architecture arm GDB thinks the target is aarch64, but it isn't. Nowadays, we are using some entries AT_PHENT and AT_HWCAP in auxv to determine whether the process is a 32-bit arm one or 64-bit aarch64 one, and get the right gdbarch. However, in the process of parsing auxv (in inf_ptrace_auxv_parse), the size of int and data pointer of target_gdbarch is used. If debug program exists (in most of cases), target_gdbarch is already set according to the debug program, which is arm in my case. Then, GDB can parse auxv successfully. However, in gdb.base/attach-pie-noexec.exp, the debug program is removed, target_gdbarch is aarch64 when GDB parse auxv, so GDB can't parse it successfully. Instead of using auxv, we check the return value of ptrace NT_ARM_VFP. If the program is an arm process, NT_ARM_VFP is OK, otherwise, error is returned. Additionally, we only return tdesc_arm_with_neon for arm process, because neon is mandatory on ARMv8. gdb: 2016-08-04 Yao Qi * aarch64-linux-nat.c (tdesc_arm_with_vfpv3): Remove the declaration. (aarch64_linux_read_description): Remove code on getting auxv and select target description on it. Select target description by the result of NT_ARM_VFP ptrace request. --- gdb/ChangeLog | 8 +++++++ gdb/aarch64-linux-nat.c | 50 +++++++++-------------------------------- 2 files changed, 19 insertions(+), 39 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 24a53a5961..35a206edcc 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,11 @@ +2016-08-04 Yao Qi + + * aarch64-linux-nat.c (tdesc_arm_with_vfpv3): Remove the + declaration. + (aarch64_linux_read_description): Remove code on getting + auxv and select target description on it. Select target + description by the result of NT_ARM_VFP ptrace request. + 2016-08-03 Tom Tromey PR python/18565: diff --git a/gdb/aarch64-linux-nat.c b/gdb/aarch64-linux-nat.c index fe1631dbbb..e4316376c5 100644 --- a/gdb/aarch64-linux-nat.c +++ b/gdb/aarch64-linux-nat.c @@ -481,7 +481,6 @@ aarch64_linux_child_post_startup_inferior (struct target_ops *self, super_post_startup_inferior (self, ptid); } -extern struct target_desc *tdesc_arm_with_vfpv3; extern struct target_desc *tdesc_arm_with_neon; /* Implement the "to_read_description" target_ops method. */ @@ -489,47 +488,20 @@ extern struct target_desc *tdesc_arm_with_neon; static const struct target_desc * aarch64_linux_read_description (struct target_ops *ops) { - CORE_ADDR at_phent; - - if (target_auxv_search (ops, AT_PHENT, &at_phent) == 1) - { - if (at_phent == sizeof (Elf64_External_Phdr)) - return tdesc_aarch64; - else - { - CORE_ADDR arm_hwcap = 0; - - if (target_auxv_search (ops, AT_HWCAP, &arm_hwcap) != 1) - return ops->beneath->to_read_description (ops->beneath); - -#ifndef COMPAT_HWCAP_VFP -#define COMPAT_HWCAP_VFP (1 << 6) -#endif -#ifndef COMPAT_HWCAP_NEON -#define COMPAT_HWCAP_NEON (1 << 12) -#endif -#ifndef COMPAT_HWCAP_VFPv3 -#define COMPAT_HWCAP_VFPv3 (1 << 13) -#endif - - if (arm_hwcap & COMPAT_HWCAP_VFP) - { - char *buf; - const struct target_desc *result = NULL; - - if (arm_hwcap & COMPAT_HWCAP_NEON) - result = tdesc_arm_with_neon; - else if (arm_hwcap & COMPAT_HWCAP_VFPv3) - result = tdesc_arm_with_vfpv3; + int ret, tid; + gdb_byte regbuf[VFP_REGS_SIZE]; + struct iovec iovec; - return result; - } + tid = ptid_get_lwp (inferior_ptid); - return NULL; - } - } + iovec.iov_base = regbuf; + iovec.iov_len = VFP_REGS_SIZE; - return tdesc_aarch64; + ret = ptrace (PTRACE_GETREGSET, tid, NT_ARM_VFP, &iovec); + if (ret == 0) + return tdesc_arm_with_neon; + else + return tdesc_aarch64; } /* Convert a native/host siginfo object, into/from the siginfo in the -- 2.34.1