Re: PING: PATCH: PR backtrace/14646: [x32] backtrace doesn't work

H.J. Lu
2012-10-09T15:32:32Z

On Mon, Oct 08, 2012 at 02:01:42PM -0700, H.J. Lu wrote:
> On Mon, Oct 08, 2012 at 10:47:26PM +0200, Mark Kettenis wrote:
> > > Date: Mon, 8 Oct 2012 13:38:21 -0700
> > > From: "H.J. Lu" <hjl.tools@gmail.com>
> > >
> > > On Mon, Oct 8, 2012 at 1:22 PM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
> > > >> Date: Mon, 8 Oct 2012 13:04:03 -0700
> > > >> From: "H.J. Lu" <hjl.tools@gmail.com>
> > > >>
> > > >> On Mon, Oct 8, 2012 at 12:48 PM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
> > > >> >> Date: Thu, 4 Oct 2012 06:57:22 -0700
> > > >> >> From: "H.J. Lu" <hjl.tools@gmail.com>
> > > >> >>
> > > >> >> On Wed, Oct 3, 2012 at 11:57 PM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
> > > >> >> >
> > > >> >> > Perhaps the user-regs.c mechanism can be used to establish eip -> pc
> > > >> >> > and esp -> sp mappings?
> > > >> >>
> > > >> >> It doesn't help as long as gdbarch_pc_regnum/gdbarch_sp_regnum
> > > >> >> are used for both frame pc/sp value and unwind pc/sp value. For x32,
> > > >> >> we want eip/esp for frame pc/sp value and rip/rsp for unwind pc/sp
> > > >> >> value.
> > > >> >
> > > >> > That probably means we need to set gdbarch_pc_regnum (and
> > > >> > gdbarch_sp_regnum) to -1 for x32.
> > > >>
> > > >> We can't set gdbarch_pc_regnum/gdbarch_sp_regnum to -1:
> > > >>
> > > >>
> > > >> GNU gdb (GDB) 7.5.50.20121008-cvs
> > > >> Copyright (C) 2012 Free Software Foundation, Inc.
> > > >> License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
> > > >> This is free software: you are free to change and redistribute it.
> > > >> There is NO WARRANTY, to the extent permitted by law. Type "show copying"
> > > >> and "show warranty" for details.
> > > >> This GDB was configured as "x86_64-unknown-linux-gnu".
> > > >> For bug reporting instructions, please see:
> > > >> <http://www.gnu.org/software/gdb/bugs/>...
> > > >> Reading symbols from
> > > >> /export/build/gnu/glibc-x32/build-x86_64-linux/elf/sln...done.
> > > >> (gdb) b main
> > > >> Breakpoint 1 at 0x400c20: file sln.c, line 50.
> > > >> (gdb) r
> > > >> Starting program: /export/build/gnu/glibc-x32/build-x86_64-linux/elf/sln
> > > >> /export/gnu/import/git/gdb/gdb/regcache.c:1062: internal-error:
> > > >> regcache_read_pc: Unable to find PC
> > > >> A problem internal to GDB has been detected,
> > > >> further debugging may prove unreliable.
> > > >> Quit this debugging session? (y or n)
> > > >
> > > > Well, obviously you'll need to implement gdbarch_read_pc() for this to
> > > > work. And probably a few more gdbarch methods.
> > >
> > > What do we gain by setting gdbarch_pc_regnum/gdbarch_sp_regnum
> > > to -1? PC and SP are RIP and RSP for x32. We need them for
> > > stack unwind. The only unusual part is they are 64-bit although
> > > x32 is a 32-bit environment. How about this change?
> >
> > Did you even try that change?
> >
> > > diff --git a/gdb/features/i386/x32-core.xml b/gdb/features/i386/x32-core.xml
> > > index 1e41417..392ce24 100644
> > > --- a/gdb/features/i386/x32-core.xml
> > > +++ b/gdb/features/i386/x32-core.xml
> > > @@ -34,7 +34,7 @@
> > > <reg name="rsi" bitsize="64" type="int64"/>
> > > <reg name="rdi" bitsize="64" type="int64"/>
> > > <reg name="rbp" bitsize="64" type="int64"/>
> > > - <reg name="rsp" bitsize="64" type="int64"/>
> > > + <reg name="rsp" bitsize="64" type="data_ptr"/>
> > > <reg name="r8" bitsize="64" type="int64"/>
> > > <reg name="r9" bitsize="64" type="int64"/>
> > > <reg name="r10" bitsize="64" type="int64"/>
> > > @@ -44,7 +44,7 @@
> > > <reg name="r14" bitsize="64" type="int64"/>
> > > <reg name="r15" bitsize="64" type="int64"/>
> > >
> > > - <reg name="rip" bitsize="64" type="uint64"/>
> > > + <reg name="rip" bitsize="64" type="code_ptr"/>
> > > <reg name="eflags" bitsize="32" type="i386_eflags"/>
> > > <reg name="cs" bitsize="32" type="int32"/>
> > > <reg name="ss" bitsize="32" type="int32"/>
>
> Here is the patch I tried. It fixes PR backtrace/14646 and PR gdb/14647.
>
>
> H.J.
> ---
> 2012-10-08 H.J. Lu <hongjiu.lu@intel.com>
>
> PR backtrace/14646
> PR gdb/14647
> * amd64-tdep.c (amd64_x32_init_abi): Don't set sp_regnum_from_eax
> nor pc_regnum_from_eax.
> * i386-tdep.c (i386_gdbarch_init): Don't use sp_regnum_from_eax
> nor pc_regnum_from_eax.
> * i386-tdep.h (gdbarch_tdep): Remove sp_regnum_from_eax and
> pc_regnum_from_eax.
> * features/i386/x32-core.xml: Use data_ptr on rsp and use
> code_ptr on rip.
> * features/i386/x32-avx-linux.c: Regenerated.
> * features/i386/x32-avx.c: Likewise.
> * features/i386/x32-linux.c: Likewise.
> * features/i386/x32.c: Likewise.
>

X32 needs to set RSP/RIP to 32-bit. Othewise, it won't work with gdbserver
since gdbserver will send 64-bit RSP/RIP while gdb sets size of RSP/RIP
to pointer size, which is 32-bit for x32. It works for x32 since the
upper 32bits of RSP/RIP are always zero for x32. OK for trunk and 7.5
branch.

Thanks.

H.J.
---
2012-10-08 H.J. Lu <hongjiu.lu@intel.com>

PR backtrace/14646
PR gdb/14647
* amd64-tdep.c (amd64_x32_init_abi): Don't set sp_regnum_from_eax
nor pc_regnum_from_eax.
* i386-tdep.c (i386_gdbarch_init): Don't use sp_regnum_from_eax
nor pc_regnum_from_eax.
* i386-tdep.h (gdbarch_tdep): Remove sp_regnum_from_eax and
pc_regnum_from_eax.
* features/i386/x32-core.xml: Use data_ptr on rsp and use
code_ptr on rip.
* features/i386/x32-avx-linux.c: Regenerated.
* features/i386/x32-avx.c: Likewise.
* features/i386/x32-linux.c: Likewise.
* features/i386/x32.c: Likewise.
* regformats/i386/x32-avx-linux.dat: Likewise.
* regformats/i386/x32-avx.dat: Likewise.
* regformats/i386/x32-linux.dat: Likewise.
* regformats/i386/x32.dat: Likewise.

diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c
index 8c5b6cc..9cee464 100644
--- a/gdb/amd64-tdep.c
+++ b/gdb/amd64-tdep.c
@@ -2943,9 +2943,6 @@ amd64_x32_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
tdesc = tdesc_x32;
tdep->tdesc = tdesc;

- tdep->sp_regnum_from_eax = AMD64_RSP_REGNUM;
- tdep->pc_regnum_from_eax = AMD64_RIP_REGNUM;
-
tdep->num_dword_regs = 17;
set_tdesc_pseudo_register_type (gdbarch, amd64_x32_pseudo_register_type);

diff --git a/gdb/features/i386/x32-avx-linux.c b/gdb/features/i386/x32-avx-linux.c
index 1f39610..6efcffb 100644
--- a/gdb/features/i386/x32-avx-linux.c
+++ b/gdb/features/i386/x32-avx-linux.c
@@ -45,7 +45,7 @@ initialize_tdesc_x32_avx_linux (void)
tdesc_create_reg (feature, "rsi", 4, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "rdi", 5, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "rbp", 6, 1, NULL, 64, "int64");
- tdesc_create_reg (feature, "rsp", 7, 1, NULL, 64, "int64");
+ tdesc_create_reg (feature, "rsp", 7, 1, NULL, 32, "data_ptr");
tdesc_create_reg (feature, "r8", 8, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "r9", 9, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "r10", 10, 1, NULL, 64, "int64");
@@ -54,7 +54,7 @@ initialize_tdesc_x32_avx_linux (void)
tdesc_create_reg (feature, "r13", 13, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "r14", 14, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "r15", 15, 1, NULL, 64, "int64");
- tdesc_create_reg (feature, "rip", 16, 1, NULL, 64, "uint64");
+ tdesc_create_reg (feature, "rip", 16, 1, NULL, 32, "code_ptr");
tdesc_create_reg (feature, "eflags", 17, 1, NULL, 32, "i386_eflags");
tdesc_create_reg (feature, "cs", 18, 1, NULL, 32, "int32");
tdesc_create_reg (feature, "ss", 19, 1, NULL, 32, "int32");
diff --git a/gdb/features/i386/x32-avx.c b/gdb/features/i386/x32-avx.c
index fb7a12c..5b6d835 100644
--- a/gdb/features/i386/x32-avx.c
+++ b/gdb/features/i386/x32-avx.c
@@ -43,7 +43,7 @@ initialize_tdesc_x32_avx (void)
tdesc_create_reg (feature, "rsi", 4, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "rdi", 5, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "rbp", 6, 1, NULL, 64, "int64");
- tdesc_create_reg (feature, "rsp", 7, 1, NULL, 64, "int64");
+ tdesc_create_reg (feature, "rsp", 7, 1, NULL, 32, "data_ptr");
tdesc_create_reg (feature, "r8", 8, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "r9", 9, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "r10", 10, 1, NULL, 64, "int64");
@@ -52,7 +52,7 @@ initialize_tdesc_x32_avx (void)
tdesc_create_reg (feature, "r13", 13, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "r14", 14, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "r15", 15, 1, NULL, 64, "int64");
- tdesc_create_reg (feature, "rip", 16, 1, NULL, 64, "uint64");
+ tdesc_create_reg (feature, "rip", 16, 1, NULL, 32, "code_ptr");
tdesc_create_reg (feature, "eflags", 17, 1, NULL, 32, "i386_eflags");
tdesc_create_reg (feature, "cs", 18, 1, NULL, 32, "int32");
tdesc_create_reg (feature, "ss", 19, 1, NULL, 32, "int32");
diff --git a/gdb/features/i386/x32-core.xml b/gdb/features/i386/x32-core.xml
index 1e41417..28db826 100644
--- a/gdb/features/i386/x32-core.xml
+++ b/gdb/features/i386/x32-core.xml
@@ -34,7 +34,7 @@
<reg name="rsi" bitsize="64" type="int64"/>
<reg name="rdi" bitsize="64" type="int64"/>
<reg name="rbp" bitsize="64" type="int64"/>
- <reg name="rsp" bitsize="64" type="int64"/>
+ <reg name="rsp" bitsize="32" type="data_ptr"/>
<reg name="r8" bitsize="64" type="int64"/>
<reg name="r9" bitsize="64" type="int64"/>
<reg name="r10" bitsize="64" type="int64"/>
@@ -44,7 +44,7 @@
<reg name="r14" bitsize="64" type="int64"/>
<reg name="r15" bitsize="64" type="int64"/>

- <reg name="rip" bitsize="64" type="uint64"/>
+ <reg name="rip" bitsize="32" type="code_ptr"/>
<reg name="eflags" bitsize="32" type="i386_eflags"/>
<reg name="cs" bitsize="32" type="int32"/>
<reg name="ss" bitsize="32" type="int32"/>
diff --git a/gdb/features/i386/x32-linux.c b/gdb/features/i386/x32-linux.c
index 387436f..d06fcbf 100644
--- a/gdb/features/i386/x32-linux.c
+++ b/gdb/features/i386/x32-linux.c
@@ -45,7 +45,7 @@ initialize_tdesc_x32_linux (void)
tdesc_create_reg (feature, "rsi", 4, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "rdi", 5, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "rbp", 6, 1, NULL, 64, "int64");
- tdesc_create_reg (feature, "rsp", 7, 1, NULL, 64, "int64");
+ tdesc_create_reg (feature, "rsp", 7, 1, NULL, 32, "data_ptr");
tdesc_create_reg (feature, "r8", 8, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "r9", 9, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "r10", 10, 1, NULL, 64, "int64");
@@ -54,7 +54,7 @@ initialize_tdesc_x32_linux (void)
tdesc_create_reg (feature, "r13", 13, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "r14", 14, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "r15", 15, 1, NULL, 64, "int64");
- tdesc_create_reg (feature, "rip", 16, 1, NULL, 64, "uint64");
+ tdesc_create_reg (feature, "rip", 16, 1, NULL, 32, "code_ptr");
tdesc_create_reg (feature, "eflags", 17, 1, NULL, 32, "i386_eflags");
tdesc_create_reg (feature, "cs", 18, 1, NULL, 32, "int32");
tdesc_create_reg (feature, "ss", 19, 1, NULL, 32, "int32");
diff --git a/gdb/features/i386/x32.c b/gdb/features/i386/x32.c
index 34e5087..679f767 100644
--- a/gdb/features/i386/x32.c
+++ b/gdb/features/i386/x32.c
@@ -43,7 +43,7 @@ initialize_tdesc_x32 (void)
tdesc_create_reg (feature, "rsi", 4, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "rdi", 5, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "rbp", 6, 1, NULL, 64, "int64");
- tdesc_create_reg (feature, "rsp", 7, 1, NULL, 64, "int64");
+ tdesc_create_reg (feature, "rsp", 7, 1, NULL, 32, "data_ptr");
tdesc_create_reg (feature, "r8", 8, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "r9", 9, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "r10", 10, 1, NULL, 64, "int64");
@@ -52,7 +52,7 @@ initialize_tdesc_x32 (void)
tdesc_create_reg (feature, "r13", 13, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "r14", 14, 1, NULL, 64, "int64");
tdesc_create_reg (feature, "r15", 15, 1, NULL, 64, "int64");
- tdesc_create_reg (feature, "rip", 16, 1, NULL, 64, "uint64");
+ tdesc_create_reg (feature, "rip", 16, 1, NULL, 32, "code_ptr");
tdesc_create_reg (feature, "eflags", 17, 1, NULL, 32, "i386_eflags");
tdesc_create_reg (feature, "cs", 18, 1, NULL, 32, "int32");
tdesc_create_reg (feature, "ss", 19, 1, NULL, 32, "int32");
diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
index 84e9794..ddb20aa 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -7705,9 +7705,6 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
tdep->num_mmx_regs = 8;
tdep->num_ymm_regs = 0;

- tdep->sp_regnum_from_eax = -1;
- tdep->pc_regnum_from_eax = -1;
-
tdesc_data = tdesc_data_alloc ();

set_gdbarch_relocate_instruction (gdbarch, i386_relocate_instruction);
@@ -7752,14 +7749,6 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
/* Support dword pseudo-register if it hasn't been disabled. */
tdep->eax_regnum = ymm0_regnum;
ymm0_regnum += tdep->num_dword_regs;
- if (tdep->sp_regnum_from_eax != -1)
- set_gdbarch_sp_regnum (gdbarch,
- (tdep->eax_regnum
- + tdep->sp_regnum_from_eax));
- if (tdep->pc_regnum_from_eax != -1)
- set_gdbarch_pc_regnum (gdbarch,
- (tdep->eax_regnum
- + tdep->pc_regnum_from_eax));
}
else
tdep->eax_regnum = -1;
diff --git a/gdb/i386-tdep.h b/gdb/i386-tdep.h
index 76afdce..5f233f5 100644
--- a/gdb/i386-tdep.h
+++ b/gdb/i386-tdep.h
@@ -149,14 +149,6 @@ struct gdbarch_tdep
of pseudo dword register support. */
int eax_regnum;

- /* Register number for SP, relative to %eax. Set this to -1 to
- indicate the absence of pseudo SP register support. */
- int sp_regnum_from_eax;
-
- /* Register number for PC, relative to %eax. Set this to -1 to
- indicate the absence of pseudo PC register support. */
- int pc_regnum_from_eax;
-
/* Number of core registers. */
int num_core_regs;

diff --git a/gdb/regformats/i386/x32-avx-linux.dat b/gdb/regformats/i386/x32-avx-linux.dat
index 1203806..f142265 100644
--- a/gdb/regformats/i386/x32-avx-linux.dat
+++ b/gdb/regformats/i386/x32-avx-linux.dat
@@ -9,7 +9,7 @@ expedite:rbp,rsp,rip
64:rsi
64:rdi
64:rbp
-64:rsp
+32:rsp
64:r8
64:r9
64:r10
@@ -18,7 +18,7 @@ expedite:rbp,rsp,rip
64:r13
64:r14
64:r15
-64:rip
+32:rip
32:eflags
32:cs
32:ss
diff --git a/gdb/regformats/i386/x32-avx.dat b/gdb/regformats/i386/x32-avx.dat
index f13bf28..62e9d4a 100644
--- a/gdb/regformats/i386/x32-avx.dat
+++ b/gdb/regformats/i386/x32-avx.dat
@@ -9,7 +9,7 @@ expedite:rbp,rsp,rip
64:rsi
64:rdi
64:rbp
-64:rsp
+32:rsp
64:r8
64:r9
64:r10
@@ -18,7 +18,7 @@ expedite:rbp,rsp,rip
64:r13
64:r14
64:r15
-64:rip
+32:rip
32:eflags
32:cs
32:ss
diff --git a/gdb/regformats/i386/x32-linux.dat b/gdb/regformats/i386/x32-linux.dat
index 6eda64a..8cb27e1 100644
--- a/gdb/regformats/i386/x32-linux.dat
+++ b/gdb/regformats/i386/x32-linux.dat
@@ -9,7 +9,7 @@ expedite:rbp,rsp,rip
64:rsi
64:rdi
64:rbp
-64:rsp
+32:rsp
64:r8
64:r9
64:r10
@@ -18,7 +18,7 @@ expedite:rbp,rsp,rip
64:r13
64:r14
64:r15
-64:rip
+32:rip
32:eflags
32:cs
32:ss
diff --git a/gdb/regformats/i386/x32.dat b/gdb/regformats/i386/x32.dat
index 6c63a8a..4bee34e 100644
--- a/gdb/regformats/i386/x32.dat
+++ b/gdb/regformats/i386/x32.dat
@@ -9,7 +9,7 @@ expedite:rbp,rsp,rip
64:rsi
64:rdi
64:rbp
-64:rsp
+32:rsp
64:r8
64:r9
64:r10
@@ -18,7 +18,7 @@ expedite:rbp,rsp,rip
64:r13
64:r14
64:r15
-64:rip
+32:rip
32:eflags
32:cs
32:ss