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Convert have_ptrace_getregset to a tri-state boolean

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have_ptrace_getregset is a tri-state variable (-1, 0, 1), and we have
some conditions like "if (have_ptrace_getregset)", which is not correct.
I'll explain why it is not correct in the following example.  This fix
to this problem to replace the test (have_ptrace_getregset) to test
(have_ptrace_getregset == 1) or (have_ptrace_getregset == -1) etc.
However Doug thinks it hinders readability
https://sourceware.org/ml/gdb-patches/2015-05/msg00692.html so I decide
to add a new enum tribool and change have_ptrace_getregset to it, in
order to make these tests more readable.

have_ptrace_getregset is initialised to -1, and is adjusted to 0 or 1 in
$ARCH_linux_read_description according to the capability of the kernel.
However, it is possible that have_ptrace_getregset is used before it is
set to 0 or 1, which means it is still -1.  This is shown below.

(gdb) run
Starting program: gdb/testsuite/gdb.base/break

Breakpoint 2, amd64_linux_fetch_inferior_registers (ops=0xceaa80, regcache=0xe72000, regnum=16) at git/gdb/amd64-linux-nat.c:128
128	{
top?p have_ptrace_getregset
$1 = TRIBOOL_UNKNOWN
top?c
Continuing.

Breakpoint 2, amd64_linux_fetch_inferior_registers (ops=0xceaa80, regcache=0xe72000, regnum=16) at git/gdb/amd64-linux-nat.c:128
128	{
top?c
Continuing.

Breakpoint 1, x86_linux_read_description (ops=0xceaa80) at git/gdb/x86-linux-nat.c:117
117	{

PTRACE_GETREGSET command is used even GDB doesn't know whether
PTRACE_GETREGSET is supported or not.  It is wrong, but works on x86.
However it doesn't work on arm-linux if the kernel doesn't support
PTRACE_GETREGSET at all.  We'll get:

(gdb) run
Starting program: gdb/testsuite/gdb.base/break
warning: Unable to fetch general register.
PC register is not available

gdb:

2015-06-23  Yao Qi  <yao.qi@linaro.org>

	* amd64-linux-nat.c (amd64_linux_fetch_inferior_registers):
	Check whether have_ptrace_getregset is TRIBOOL_TRUE explicitly.
	(amd64_linux_store_inferior_registers): Likewise.
	* arm-linux-nat.c (fetch_fpregister): Likewise.
	(fetch_fpregs, store_fpregister): Likewise.
	(store_fpregister, store_fpregs): Likewise.
	(fetch_register, fetch_regs): Likewise.
	(store_register, store_regs): Likewise.
	(fetch_vfp_regs, store_vfp_regs): Likewise.
	(arm_linux_read_description): Check have_ptrace_getregset is
	TRIBOOL_UNKNOWN.  Set have_ptrace_getregset to TRIBOOL_TRUE
	or TRIBOOL_FALSE.
	* i386-linux-nat.c (fetch_xstateregs): Check
	have_ptrace_getregset is not TRIBOOL_TRUE.
	(store_xstateregs): Likewise.
	* linux-nat.c (have_ptrace_getregset): Change its type to
	enum tribool.
	* linux-nat.h (tribool): New enum.
	* x86-linux-nat.c (x86_linux_read_description): Use enum tribool.
	Check whether have_ptrace_getregset is TRIBOOL_TRUE.
This commit is contained in:
Yao Qi 2015-06-23 14:03:11 +01:00
parent c217058957
commit 0bdb2f7849
7 changed files with 53 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
gdb/ChangeLog
View File

@ -1,3 +1,26 @@
2015-06-23 Yao Qi <yao.qi@linaro.org>
* amd64-linux-nat.c (amd64_linux_fetch_inferior_registers):
Check whether have_ptrace_getregset is TRIBOOL_TRUE explicitly.
(amd64_linux_store_inferior_registers): Likewise.
* arm-linux-nat.c (fetch_fpregister): Likewise.
(fetch_fpregs, store_fpregister): Likewise.
(store_fpregister, store_fpregs): Likewise.
(fetch_register, fetch_regs): Likewise.
(store_register, store_regs): Likewise.
(fetch_vfp_regs, store_vfp_regs): Likewise.
(arm_linux_read_description): Check have_ptrace_getregset is
TRIBOOL_UNKNOWN. Set have_ptrace_getregset to TRIBOOL_TRUE
or TRIBOOL_FALSE.
* i386-linux-nat.c (fetch_xstateregs): Check
have_ptrace_getregset is not TRIBOOL_TRUE.
(store_xstateregs): Likewise.
* linux-nat.c (have_ptrace_getregset): Change its type to
enum tribool.
* linux-nat.h (tribool): New enum.
* x86-linux-nat.c (x86_linux_read_description): Use enum tribool.
Check whether have_ptrace_getregset is TRIBOOL_TRUE.
2015-06-19 Doug Evans <dje@google.com>
* NEWS: Mention Sun's version of stabs is no longer supported.

4
gdb/amd64-linux-nat.c
View File

@ -150,7 +150,7 @@ amd64_linux_fetch_inferior_registers (struct target_ops *ops,
{
elf_fpregset_t fpregs;
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
{
char xstateregs[X86_XSTATE_MAX_SIZE];
struct iovec iov;
@ -209,7 +209,7 @@ amd64_linux_store_inferior_registers (struct target_ops *ops,
{
elf_fpregset_t fpregs;
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
{
char xstateregs[X86_XSTATE_MAX_SIZE];
struct iovec iov;

36
gdb/arm-linux-nat.c
View File

@ -95,7 +95,7 @@ fetch_fpregister (struct regcache *regcache, int regno)
tid = GET_THREAD_ID (inferior_ptid);
/* Read the floating point state. */
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
{
struct iovec iov;
@ -136,7 +136,7 @@ fetch_fpregs (struct regcache *regcache)
tid = GET_THREAD_ID (inferior_ptid);
/* Read the floating point state. */
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
{
struct iovec iov;
@ -176,7 +176,7 @@ store_fpregister (const struct regcache *regcache, int regno)
tid = GET_THREAD_ID (inferior_ptid);
/* Read the floating point state. */
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
{
struct iovec iov;
@ -203,7 +203,7 @@ store_fpregister (const struct regcache *regcache, int regno)
if (regno >= ARM_F0_REGNUM && regno <= ARM_F7_REGNUM)
collect_nwfpe_register (regcache, regno, fp);
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
{
struct iovec iov;
@ -235,7 +235,7 @@ store_fpregs (const struct regcache *regcache)
tid = GET_THREAD_ID (inferior_ptid);
/* Read the floating point state. */
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
{
elf_fpregset_t fpregs;
struct iovec iov;
@ -263,7 +263,7 @@ store_fpregs (const struct regcache *regcache)
if (REG_VALID == regcache_register_status (regcache, regno))
collect_nwfpe_register (regcache, regno, fp);
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
{
struct iovec iov;
@ -294,7 +294,7 @@ fetch_register (struct regcache *regcache, int regno)
/* Get the thread id for the ptrace call. */
tid = GET_THREAD_ID (inferior_ptid);
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
{
struct iovec iov;
@ -347,7 +347,7 @@ fetch_regs (struct regcache *regcache)
/* Get the thread id for the ptrace call. */
tid = GET_THREAD_ID (inferior_ptid);
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
{
struct iovec iov;
@ -397,7 +397,7 @@ store_register (const struct regcache *regcache, int regno)
tid = GET_THREAD_ID (inferior_ptid);
/* Get the general registers from the process. */
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
{
struct iovec iov;
@ -424,7 +424,7 @@ store_register (const struct regcache *regcache, int regno)
regcache_raw_collect (regcache, ARM_PC_REGNUM,
(char *) &regs[ARM_PC_REGNUM]);
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
{
struct iovec iov;
@ -453,7 +453,7 @@ store_regs (const struct regcache *regcache)
tid = GET_THREAD_ID (inferior_ptid);
/* Fetch the general registers. */
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
{
struct iovec iov;
@ -481,7 +481,7 @@ store_regs (const struct regcache *regcache)
regcache_raw_collect (regcache, ARM_PS_REGNUM,
(char *) &regs[ARM_CPSR_GREGNUM]);
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
{
struct iovec iov;
@ -593,7 +593,7 @@ fetch_vfp_regs (struct regcache *regcache)
/* Get the thread id for the ptrace call. */
tid = GET_THREAD_ID (inferior_ptid);
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
{
struct iovec iov;
@ -629,7 +629,7 @@ store_vfp_regs (const struct regcache *regcache)
/* Get the thread id for the ptrace call. */
tid = GET_THREAD_ID (inferior_ptid);
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
{
struct iovec iov;
@ -653,7 +653,7 @@ store_vfp_regs (const struct regcache *regcache)
regcache_raw_collect (regcache, ARM_FPSCR_REGNUM,
(char *) regbuf + 32 * 8);
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
{
struct iovec iov;
@ -797,7 +797,7 @@ arm_linux_read_description (struct target_ops *ops)
{
CORE_ADDR arm_hwcap = 0;
if (have_ptrace_getregset == -1)
if (have_ptrace_getregset == TRIBOOL_UNKNOWN)
{
elf_gregset_t gpregs;
struct iovec iov;
@ -808,9 +808,9 @@ arm_linux_read_description (struct target_ops *ops)
/* Check if PTRACE_GETREGSET works. */
if (ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS, &iov) < 0)
have_ptrace_getregset = 0;
have_ptrace_getregset = TRIBOOL_FALSE;
else
have_ptrace_getregset = 1;
have_ptrace_getregset = TRIBOOL_TRUE;
}
if (target_auxv_search (ops, AT_HWCAP, &arm_hwcap) != 1)

4
gdb/i386-linux-nat.c
View File

@ -327,7 +327,7 @@ fetch_xstateregs (struct regcache *regcache, int tid)
char xstateregs[X86_XSTATE_MAX_SIZE];
struct iovec iov;
if (!have_ptrace_getregset)
if (have_ptrace_getregset != TRIBOOL_TRUE)
return 0;
iov.iov_base = xstateregs;
@ -350,7 +350,7 @@ store_xstateregs (const struct regcache *regcache, int tid, int regno)
char xstateregs[X86_XSTATE_MAX_SIZE];
struct iovec iov;
if (!have_ptrace_getregset)
if (have_ptrace_getregset != TRIBOOL_TRUE)
return 0;
iov.iov_base = xstateregs;

2
gdb/linux-nat.c
View File

@ -166,7 +166,7 @@ blocked. */
#endif
/* Does the current host support PTRACE_GETREGSET? */
int have_ptrace_getregset = -1;
enum tribool have_ptrace_getregset = TRIBOOL_UNKNOWN;
/* The single-threaded native GNU/Linux target_ops. We save a pointer for
the use of the multi-threaded target. */

3
gdb/linux-nat.h
View File

@ -116,7 +116,8 @@ struct lwp_info
extern struct lwp_info *lwp_list;
/* Does the current host support PTRACE_GETREGSET? */
extern int have_ptrace_getregset;
enum tribool { TRIBOOL_UNKNOWN = -1, TRIBOOL_FALSE = 0, TRIBOOL_TRUE = 1 };
extern enum tribool have_ptrace_getregset;
/* Iterate over each active thread (light-weight process). */
#define ALL_LWPS(LP) \

10
gdb/x86-linux-nat.c
View File

@ -162,13 +162,13 @@ x86_linux_read_description (struct target_ops *ops)
if (ptrace (PTRACE_GETFPXREGS, tid, 0, (int) &fpxregs) < 0)
{
have_ptrace_getfpxregs = 0;
have_ptrace_getregset = 0;
have_ptrace_getregset = TRIBOOL_FALSE;
return tdesc_i386_mmx_linux;
}
}
#endif
if (have_ptrace_getregset == -1)
if (have_ptrace_getregset == TRIBOOL_UNKNOWN)
{
uint64_t xstateregs[(X86_XSTATE_SSE_SIZE / sizeof (uint64_t))];
struct iovec iov;
@ -179,10 +179,10 @@ x86_linux_read_description (struct target_ops *ops)
/* Check if PTRACE_GETREGSET works. */
if (ptrace (PTRACE_GETREGSET, tid,
(unsigned int) NT_X86_XSTATE, &iov) < 0)
have_ptrace_getregset = 0;
have_ptrace_getregset = TRIBOOL_FALSE;
else
{
have_ptrace_getregset = 1;
have_ptrace_getregset = TRIBOOL_TRUE;
/* Get XCR0 from XSAVE extended state. */
xcr0 = xstateregs[(I386_LINUX_XSAVE_XCR0_OFFSET
@ -194,7 +194,7 @@ x86_linux_read_description (struct target_ops *ops)
PTRACE_GETREGSET is not available then set xcr0_features_bits to
zero so that the "no-features" descriptions are returned by the
switches below. */
if (have_ptrace_getregset)
if (have_ptrace_getregset == TRIBOOL_TRUE)
xcr0_features_bits = xcr0 & X86_XSTATE_ALL_MASK;
else
xcr0_features_bits = 0;