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Re: [PATCH] Patch 2 of 2 for aarch64 ILP32 support in gdb
- From: Steve Ellcey <sellcey at caviumnetworks dot com>
- To: Yao Qi <qiyaoltc at gmail dot com>
- Cc: binutils <binutils at sourceware dot org>, gdb-patches <gdb-patches at sourceware dot org>, Yury Norov <ynorov at caviumnetworks dot com>, <schwab at suse dot de>, "Pinski, Andrew" <Andrew dot Pinski at cavium dot com>
- Date: Tue, 31 Jan 2017 15:15:59 -0800
- Subject: Re: [PATCH] Patch 2 of 2 for aarch64 ILP32 support in gdb
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On Sun, 2017-01-29 at 22:40 +0000, Yao Qi wrote:
> This changes the word size and address size, which is used to determine
> the inferior is arm or aarch64 by checking "bits_per_word == 32" in
> multi-arch debugging. You can find some instances of such check in
> aarch64-linux-nat.c. If the bits_per_word is 32 in ILP32, GDB thinks
> the inferior is an ARM one, rather than an AArch64 ILP32 one. which is
> wrong. We need to tweak the condition above to correctly identify the
> ARM inferior.
>
> Do you compare the ILP32 gdb test result with normal aarch64 one?
OK, I fixed up arch64-linux-nat.c and didn't find any other places were
the bits_per_word was being checked and I fixed the TRUE/true
FALSE/false constants. If I run gdb without any changes or with this
patch but debugging 64 bit code I get around 500 failures. The number
doesn't seem to be constant, I have gotten anywhere from 488 to 503
failures testing the same code. My last run had:
# of expected passes 30428
# of unexpected failures 503
# of expected failures 53
# of unknown successes 2
# of known failures 64
# of untested testcases 66
# of unresolved testcases 6
# of unsupported tests 293
Many of the failures seem to be thread related and I see a lot of
messages about timeouts and 'program is no longer running'. When
I run gdb on 32 bit programs with:
RUNTESTFLAGS="--target_board=unix/-mabi=ilp32"
I get 700+ failures. My last run had:
# of expected passes 29482
# of unexpected failures 740
# of expected failures 30
# of unknown successes 2
# of known failures 65
# of untested testcases 79
# of unresolved testcases 4
# of unsupported tests 288
So there are more failures in ILP32 mode but there seem to be enough
passes that I think it still makes sense to check in the patch to get
some gdb functionality working.
Here is the latest patch.
Steve Ellcey
sellcey@cavium.com
gdb ChangeLog:
2017-01-31 Andrew Pinski <apinski@cavium.com>
Steve Ellcey <sellcey@cavium.com>
Yao Qi <yao.qi@linaro.org>
* aarch64-linux-nat.c (IS_ARM32): New macro.
(fetch_gregs_from_thread): Use IS_ARM32 macro.
(store_gregs_to_thread): Ditto.
(fetch_fpregs_from_thread): Ditto.
(store_fpregs_to_thread): Ditto.
(ps_get_thread_area): Ditto.
(aarch64_linux_siginfo_fixup): Ditto.
* aarch64-linux-tdep.c (aarch64_linux_init_abi): Set link
map offsets to 32 or 64 bits.
* aarch64-tdep.c (aarch64_ilp32_register_type): New function.
(aarch64_gdbarch_init): Setup ILP32 support.
Make sure the gdbarches have compatible ilp32 flags.
Set long and ptr sizes correctly for ilp32.
* aarch64-tdep.h (gdbarch_tdep) <ilp32>: New field.
gdbserver ChangeLog:
2017-01-31 Andrew Pinski <apinski@cavium.com>
Steve Ellcey <sellcey@cavium.com>
* linux-aarch64-low.c (aarch64_linux_read_description): Use
machine instead of is_elf64 to determine architecture. Give an
error when using 32 bit gdbserver on 64 bit program.
diff --git a/gdb/aarch64-linux-nat.c b/gdb/aarch64-linux-nat.c
index 0d472e2..f6fd19a 100644
--- a/gdb/aarch64-linux-nat.c
+++ b/gdb/aarch64-linux-nat.c
@@ -49,6 +49,9 @@
#define TRAP_HWBKPT 0x0004
#endif
+/* Check if we are on arm (as opposed to aarch64). */
+#define IS_ARM32(arch) (gdbarch_bfd_arch_info(arch)->mach == bfd_mach_arm)
+
/* Per-process data. We don't bind this to a per-inferior registry
because of targets like x86 GNU/Linux that need to keep track of
processes that aren't bound to any inferior (e.g., fork children,
@@ -166,7 +169,7 @@ fetch_gregs_from_thread (struct regcache *regcache)
tid = ptid_get_lwp (inferior_ptid);
iovec.iov_base = ®s;
- if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
+ if (IS_ARM32 (gdbarch))
iovec.iov_len = 18 * 4;
else
iovec.iov_len = sizeof (regs);
@@ -175,7 +178,7 @@ fetch_gregs_from_thread (struct regcache *regcache)
if (ret < 0)
perror_with_name (_("Unable to fetch general registers."));
- if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
+ if (IS_ARM32 (gdbarch))
aarch32_gp_regcache_supply (regcache, (uint32_t *) regs, 1);
else
{
@@ -203,7 +206,7 @@ store_gregs_to_thread (const struct regcache *regcache)
tid = ptid_get_lwp (inferior_ptid);
iovec.iov_base = ®s;
- if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
+ if (IS_ARM32 (gdbarch))
iovec.iov_len = 18 * 4;
else
iovec.iov_len = sizeof (regs);
@@ -212,7 +215,7 @@ store_gregs_to_thread (const struct regcache *regcache)
if (ret < 0)
perror_with_name (_("Unable to fetch general registers."));
- if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
+ if (IS_ARM32 (gdbarch))
aarch32_gp_regcache_collect (regcache, (uint32_t *) regs, 1);
else
{
@@ -248,7 +251,7 @@ fetch_fpregs_from_thread (struct regcache *regcache)
iovec.iov_base = ®s;
- if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
+ if (IS_ARM32 (gdbarch))
{
iovec.iov_len = VFP_REGS_SIZE;
@@ -295,7 +298,7 @@ store_fpregs_to_thread (const struct regcache *regcache)
iovec.iov_base = ®s;
- if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
+ if (IS_ARM32 (gdbarch))
{
iovec.iov_len = VFP_REGS_SIZE;
@@ -328,7 +331,7 @@ store_fpregs_to_thread (const struct regcache *regcache)
(char *) ®s.fpcr);
}
- if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
+ if (IS_ARM32 (gdbarch))
{
ret = ptrace (PTRACE_SETREGSET, tid, NT_ARM_VFP, &iovec);
if (ret < 0)
@@ -460,8 +463,7 @@ ps_err_e
ps_get_thread_area (struct ps_prochandle *ph,
lwpid_t lwpid, int idx, void **base)
{
- int is_64bit_p
- = (gdbarch_bfd_arch_info (target_gdbarch ())->bits_per_word == 64);
+ int is_64bit_p = !IS_ARM32 (target_gdbarch ());
return aarch64_ps_get_thread_area (ph, lwpid, idx, base, is_64bit_p);
}
@@ -517,7 +519,7 @@ aarch64_linux_siginfo_fixup (siginfo_t *native, gdb_byte *inf, int direction)
/* Is the inferior 32-bit? If so, then do fixup the siginfo
object. */
- if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
+ if (IS_ARM32 (gdbarch))
{
if (direction == 0)
aarch64_compat_siginfo_from_siginfo ((struct compat_siginfo *) inf,
diff --git a/gdb/aarch64-linux-tdep.c b/gdb/aarch64-linux-tdep.c
index b94ccb2..6d0c3bd 100644
--- a/gdb/aarch64-linux-tdep.c
+++ b/gdb/aarch64-linux-tdep.c
@@ -1000,8 +1000,12 @@ aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
linux_init_abi (info, gdbarch);
- set_solib_svr4_fetch_link_map_offsets (gdbarch,
- svr4_lp64_fetch_link_map_offsets);
+ if (tdep->ilp32)
+ set_solib_svr4_fetch_link_map_offsets (gdbarch,
+ svr4_ilp32_fetch_link_map_offsets);
+ else
+ set_solib_svr4_fetch_link_map_offsets (gdbarch,
+ svr4_lp64_fetch_link_map_offsets);
/* Enable TLS support. */
set_gdbarch_fetch_tls_load_module_address (gdbarch,
diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index 801c03d..67f1a2e 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -2091,6 +2091,22 @@ aarch64_gen_return_address (struct gdbarch *gdbarch,
}
+/* Implement the "register_type" gdbarch method.
+ Adjust the register type of $PC and $SP on ILP32. */
+
+static struct type *
+aarch64_ilp32_register_type (struct gdbarch *gdbarch, int regnum)
+{
+ struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+ gdb_assert (tdep->ilp32);
+
+ if (regnum == AARCH64_SP_REGNUM || regnum == AARCH64_PC_REGNUM)
+ return builtin_type (gdbarch)->builtin_uint64;
+ else
+ return tdesc_register_type (gdbarch, regnum);
+}
+
/* Return the pseudo register name corresponding to register regnum. */
static const char *
@@ -2851,6 +2867,10 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
const struct tdesc_feature *feature;
int num_regs = 0;
int num_pseudo_regs = 0;
+ bool ilp32 = false;
+
+ if (info.bfd_arch_info->mach == bfd_mach_aarch64_ilp32)
+ ilp32 = true;
/* Ensure we always have a target descriptor. */
if (!tdesc_has_registers (tdesc))
@@ -2908,6 +2928,9 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
best_arch != NULL;
best_arch = gdbarch_list_lookup_by_info (best_arch->next, &info))
{
+ /* ILP32 and LP64 are incompatible. */
+ if (gdbarch_tdep (arches->gdbarch)->ilp32 != ilp32)
+ continue;
/* Found a match. */
break;
}
@@ -2926,6 +2949,7 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
tdep->lowest_pc = 0x20;
tdep->jb_pc = -1; /* Longjump support not enabled by default. */
tdep->jb_elt_size = 8;
+ tdep->ilp32 = ilp32;
set_gdbarch_push_dummy_call (gdbarch, aarch64_push_dummy_call);
set_gdbarch_frame_align (gdbarch, aarch64_frame_align);
@@ -2968,9 +2992,9 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
set_gdbarch_float_bit (gdbarch, 32);
set_gdbarch_double_bit (gdbarch, 64);
set_gdbarch_long_double_bit (gdbarch, 128);
- set_gdbarch_long_bit (gdbarch, 64);
+ set_gdbarch_long_bit (gdbarch, ilp32 ? 32 : 64);
set_gdbarch_long_long_bit (gdbarch, 64);
- set_gdbarch_ptr_bit (gdbarch, 64);
+ set_gdbarch_ptr_bit (gdbarch, ilp32 ? 32 : 64);
set_gdbarch_char_signed (gdbarch, 0);
set_gdbarch_float_format (gdbarch, floatformats_ieee_single);
set_gdbarch_double_format (gdbarch, floatformats_ieee_double);
@@ -3012,6 +3036,13 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
tdesc_use_registers (gdbarch, tdesc, tdesc_data);
+ if (ilp32)
+ {
+ /* Override tdesc_register_type to adjust the types of $PC and
+ $SP in ILP32. */
+ set_gdbarch_register_type (gdbarch, aarch64_ilp32_register_type);
+ }
+
/* Add standard register aliases. */
for (i = 0; i < ARRAY_SIZE (aarch64_register_aliases); i++)
user_reg_add (gdbarch, aarch64_register_aliases[i].name,
diff --git a/gdb/aarch64-tdep.h b/gdb/aarch64-tdep.h
index 85c6a97..87d36b6 100644
--- a/gdb/aarch64-tdep.h
+++ b/gdb/aarch64-tdep.h
@@ -97,6 +97,9 @@ struct gdbarch_tdep
/* syscall record. */
int (*aarch64_syscall_record) (struct regcache *regcache, unsigned long svc_number);
+ /* If this is ILP32 or LP64. */
+ bool ilp32;
+
};
extern struct target_desc *tdesc_aarch64;
diff --git a/gdb/gdbserver/linux-aarch64-low.c b/gdb/gdbserver/linux-aarch64-low.c
index 334310b..e31d5c5 100644
--- a/gdb/gdbserver/linux-aarch64-low.c
+++ b/gdb/gdbserver/linux-aarch64-low.c
@@ -484,7 +484,12 @@ aarch64_linux_read_description (void)
is_elf64 = linux_pid_exe_is_elf_64_file (tid, &machine);
- if (is_elf64)
+ /* There are problems with ptrace when gdbserver is 32 bits and the
+ program being debugged is 64 bits. */
+ if (sizeof (void *) == 4 && is_elf64)
+ error (_("Can't debug 64-bit process with 32-bit GDBserver"));
+
+ if (machine == EM_AARCH64)
return tdesc_aarch64;
else
return tdesc_arm_with_neon;