From ee4fbcfa26eb4a2a3666f7c1cc31447c3cffa023 Mon Sep 17 00:00:00 2001 From: Alan Hayward Date: Fri, 22 Mar 2019 10:00:28 +0000 Subject: [PATCH] AArch64: Use HWCAP to detect pauth feature Add aarch64_get_hwcap functions for reading the HWCAP. From this extract the PACA value and use this to enable pauth. gdb/ChangeLog: * aarch64-linux-nat.c (aarch64_linux_nat_target::read_description): Read PACA hwcap. * aarch64-linux-tdep.c (aarch64_linux_core_read_description): Likewise. (aarch64_linux_get_hwcap): New function. * aarch64-linux-tdep.h (AARCH64_HWCAP_PACA): New define. (aarch64_linux_get_hwcap): New declaration. gdb/gdbserver/ChangeLog: * linux-aarch64-low.c (AARCH64_HWCAP_PACA): New define. (aarch64_get_hwcap): New function. (aarch64_arch_setup): Read APIA hwcap. --- gdb/ChangeLog | 11 +++++++++++ gdb/aarch64-linux-nat.c | 7 +++++-- gdb/aarch64-linux-tdep.c | 16 +++++++++++---- gdb/aarch64-linux-tdep.h | 6 ++++++ gdb/gdbserver/ChangeLog | 7 +++++++ gdb/gdbserver/linux-aarch64-low.c | 33 +++++++++++++++++++++++++++++-- 6 files changed, 72 insertions(+), 8 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 743f510b295..bd09e4fd73c 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,14 @@ +2019-03-22 Alan Hayward + Jiong Wang + + * aarch64-linux-nat.c + (aarch64_linux_nat_target::read_description): Read PACA hwcap. + * aarch64-linux-tdep.c + (aarch64_linux_core_read_description): Likewise. + (aarch64_linux_get_hwcap): New function. + * aarch64-linux-tdep.h (AARCH64_HWCAP_PACA): New define. + (aarch64_linux_get_hwcap): New declaration. + 2019-03-22 Alan Hayward Jiong Wang diff --git a/gdb/aarch64-linux-nat.c b/gdb/aarch64-linux-nat.c index f58a41e1955..9572055d9f4 100644 --- a/gdb/aarch64-linux-nat.c +++ b/gdb/aarch64-linux-nat.c @@ -606,8 +606,11 @@ aarch64_linux_nat_target::read_description () if (ret == 0) return tdesc_arm_with_neon; - /* pauth not yet supported. */ - return aarch64_read_description (aarch64_sve_get_vq (tid), false); + CORE_ADDR hwcap = 0; + bool pauth_p = aarch64_linux_get_hwcap (this, &hwcap) + && (hwcap & AARCH64_HWCAP_PACA); + + return aarch64_read_description (aarch64_sve_get_vq (tid), pauth_p); } /* Convert a native/host siginfo object, into/from the siginfo in the diff --git a/gdb/aarch64-linux-tdep.c b/gdb/aarch64-linux-tdep.c index 445019accc7..d7db23ef38e 100644 --- a/gdb/aarch64-linux-tdep.c +++ b/gdb/aarch64-linux-tdep.c @@ -637,12 +637,11 @@ aarch64_linux_core_read_description (struct gdbarch *gdbarch, { CORE_ADDR aarch64_hwcap = 0; - if (target_auxv_search (target, AT_HWCAP, &aarch64_hwcap) != 1) - return NULL; + if (!aarch64_linux_get_hwcap (target, &aarch64_hwcap)) + return nullptr; - /* pauth not yet supported. */ return aarch64_read_description (aarch64_linux_core_read_vq (gdbarch, abfd), - false); + aarch64_hwcap & AARCH64_HWCAP_PACA); } /* Implementation of `gdbarch_stap_is_single_operand', as defined in @@ -1420,6 +1419,15 @@ aarch64_linux_gcc_target_options (struct gdbarch *gdbarch) return NULL; } +/* See aarch64-linux-tdep.h. */ + +bool +aarch64_linux_get_hwcap (struct target_ops *target, CORE_ADDR *hwcap) +{ + *hwcap = 0; + return target_auxv_search (target, AT_HWCAP, hwcap) == 1; +} + static void aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) { diff --git a/gdb/aarch64-linux-tdep.h b/gdb/aarch64-linux-tdep.h index 814222ead0c..e9f7c9bccf4 100644 --- a/gdb/aarch64-linux-tdep.h +++ b/gdb/aarch64-linux-tdep.h @@ -36,4 +36,10 @@ extern const struct regset aarch64_linux_gregset; extern const struct regset aarch64_linux_fpregset; +/* Matches HWCAP_PACA in kernel header arch/arm64/include/uapi/asm/hwcap.h. */ +#define AARCH64_HWCAP_PACA (1 << 30) + +/* Fetch the AT_HWCAP entry from the auxv vector for the given TARGET. */ +bool aarch64_linux_get_hwcap (struct target_ops *target, CORE_ADDR *hwcap); + #endif /* AARCH64_LINUX_TDEP_H */ diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog index 9fdbe1d866e..3b585ca9923 100644 --- a/gdb/gdbserver/ChangeLog +++ b/gdb/gdbserver/ChangeLog @@ -1,3 +1,10 @@ +2019-03-22 Alan Hayward + Jiong Wang + + * linux-aarch64-low.c (AARCH64_HWCAP_PACA): New define. + (aarch64_get_hwcap): New function. + (aarch64_arch_setup): Read APIA hwcap. + 2019-03-22 Alan Hayward Jiong Wang diff --git a/gdb/gdbserver/linux-aarch64-low.c b/gdb/gdbserver/linux-aarch64-low.c index db329da4dc9..e2e25f0e27a 100644 --- a/gdb/gdbserver/linux-aarch64-low.c +++ b/gdb/gdbserver/linux-aarch64-low.c @@ -485,6 +485,33 @@ aarch64_linux_new_fork (struct process_info *parent, *child->priv->arch_private = *parent->priv->arch_private; } +/* Matches HWCAP_PACA in kernel header arch/arm64/include/uapi/asm/hwcap.h. */ +#define AARCH64_HWCAP_PACA (1 << 30) + +/* Fetch the AT_HWCAP entry from the auxv vector. */ + +static bool +aarch64_get_hwcap (unsigned long *valp) +{ + unsigned char *data = (unsigned char *) alloca (16); + int offset = 0; + + while ((*the_target->read_auxv) (offset, data, 16) == 16) + { + unsigned long *data_p = (unsigned long *)data; + if (data_p[0] == AT_HWCAP) + { + *valp = data_p[1]; + return true; + } + + offset += 16; + } + + *valp = 0; + return false; +} + /* Implementation of linux_target_ops method "arch_setup". */ static void @@ -501,8 +528,10 @@ aarch64_arch_setup (void) if (is_elf64) { uint64_t vq = aarch64_sve_get_vq (tid); - /* pauth not yet supported. */ - current_process ()->tdesc = aarch64_linux_read_description (vq, false); + unsigned long hwcap = 0; + bool pauth_p = aarch64_get_hwcap (&hwcap) && (hwcap & AARCH64_HWCAP_PACA); + + current_process ()->tdesc = aarch64_linux_read_description (vq, pauth_p); } else current_process ()->tdesc = tdesc_arm_with_neon; -- 2.30.2