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[PATCH] Revamp legacy GNU/Linux i386 native support
- From: Mark Kettenis <kettenis at chello dot nl>
- To: gdb-patches at sources dot redhat dot com
- Date: Sat, 9 Nov 2002 22:34:17 +0100 (CET)
- Subject: [PATCH] Revamp legacy GNU/Linux i386 native support
An attempt to remove the usage of deprecated GDB features in
i386-linux-tdep.c led me to rewrite bits of code that are used on
older Linux kernels.
I tested this on a newer Linux kernel by initializing
have_ptrace_getregs to 0 instead of 1, and that seems to work fine.
Committed.
Mark
Index: ChangeLog
from Mark Kettenis <kettenis@gnu.org>
* i386-linux-nat.c (ORIG_EAX): Define to -1 if not already
defined.
(regmap): Extend to cover all registers.
(PT_READ_U, PT_WRITE_U, PTRACE_XFER_TYPE,
OLD_CANNOT_FETCH_REGISTERS, OLD_CANNOT_STORE_REGISTERS): Remove
definitions.
(fetch_register, sore_register): Simplify.
(old_fetch_inferior_registers, old_store_inferior_registers):
Remove functions.
(cannot_fetch_register, cannot_store_register): Change
implementation to use regmap array to decide which registers
cannot be fetched/stored. This removes $orig_eax from the
registers that cannot be fetched/stored.
(fetch_inferior_registers): Call fetch_register directly instead
of calling old_fetch_inferior_registers.
(store_inferior_registers): Call store_register directly instead
of calling old_store_inferior_registers.
(i386_linux_dr_get): Replace PT_READ_U with PTRACE_PEEKUSER.
(i386_linux_dr_set): Replace PT_WRITE_U with PTRACE_POKEUSER.
* config/i386/nm-linux.h (U_REGS_OFFSET): Remove definition.
Index: i386-linux-nat.c
===================================================================
RCS file: /cvs/src/src/gdb/i386-linux-nat.c,v
retrieving revision 1.42
diff -u -p -r1.42 i386-linux-nat.c
--- i386-linux-nat.c 1 Sep 2002 22:05:42 -0000 1.42
+++ i386-linux-nat.c 9 Nov 2002 21:29:29 -0000
@@ -34,6 +34,10 @@
#include <sys/reg.h>
#endif
+#ifndef ORIG_EAX
+#define ORIG_EAX -1
+#endif
+
#ifdef HAVE_SYS_DEBUGREG_H
#include <sys/debugreg.h>
#endif
@@ -90,7 +94,15 @@ static int regmap[] =
EAX, ECX, EDX, EBX,
UESP, EBP, ESI, EDI,
EIP, EFL, CS, SS,
- DS, ES, FS, GS
+ DS, ES, FS, GS,
+ -1, -1, -1, -1, /* st0, st1, st2, st3 */
+ -1, -1, -1, -1, /* st4, st5, st6, st7 */
+ -1, -1, -1, -1, /* fctrl, fstat, ftag, fiseg */
+ -1, -1, -1, -1, /* fioff, foseg, fooff, fop */
+ -1, -1, -1, -1, /* xmm0, xmm1, xmm2, xmm3 */
+ -1, -1, -1, -1, /* xmm4, xmm5, xmm6, xmm6 */
+ -1, /* mxcsr */
+ ORIG_EAX
};
/* Which ptrace request retrieves which registers?
@@ -148,155 +160,58 @@ kernel_u_size (void)
}
-/* Fetching registers directly from the U area, one at a time. */
-
-/* FIXME: kettenis/2000-03-05: This duplicates code from `inptrace.c'.
- The problem is that we define FETCH_INFERIOR_REGISTERS since we
- want to use our own versions of {fetch,store}_inferior_registers
- that use the GETREGS request. This means that the code in
- `infptrace.c' is #ifdef'd out. But we need to fall back on that
- code when GDB is running on top of a kernel that doesn't support
- the GETREGS request. I want to avoid changing `infptrace.c' right
- now. */
-
-#ifndef PT_READ_U
-#define PT_READ_U PTRACE_PEEKUSR
-#endif
-#ifndef PT_WRITE_U
-#define PT_WRITE_U PTRACE_POKEUSR
-#endif
-
-/* Default the type of the ptrace transfer to int. */
-#ifndef PTRACE_XFER_TYPE
-#define PTRACE_XFER_TYPE int
-#endif
-
-/* Registers we shouldn't try to fetch. */
-#define OLD_CANNOT_FETCH_REGISTER(regno) ((regno) >= I386_NUM_GREGS)
+/* Accessing registers through the U area, one at a time. */
/* Fetch one register. */
static void
fetch_register (int regno)
{
- /* This isn't really an address. But ptrace thinks of it as one. */
- CORE_ADDR regaddr;
- char mess[128]; /* For messages */
- register int i;
- unsigned int offset; /* Offset of registers within the u area. */
- char buf[MAX_REGISTER_RAW_SIZE];
int tid;
+ int val;
- if (OLD_CANNOT_FETCH_REGISTER (regno))
+ gdb_assert (!have_ptrace_getregs);
+ if (cannot_fetch_register (regno))
{
- memset (buf, '\0', REGISTER_RAW_SIZE (regno)); /* Supply zeroes */
- supply_register (regno, buf);
+ supply_register (regno, NULL);
return;
}
- /* Overload thread id onto process id */
+ /* GNU/Linux LWP ID's are process ID's. */
if ((tid = TIDGET (inferior_ptid)) == 0)
- tid = PIDGET (inferior_ptid); /* no thread id, just use process id */
-
- offset = U_REGS_OFFSET;
-
- regaddr = register_addr (regno, offset);
- for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE))
- {
- errno = 0;
- *(PTRACE_XFER_TYPE *) & buf[i] = ptrace (PT_READ_U, tid,
- (PTRACE_ARG3_TYPE) regaddr, 0);
- regaddr += sizeof (PTRACE_XFER_TYPE);
- if (errno != 0)
- {
- sprintf (mess, "reading register %s (#%d)",
- REGISTER_NAME (regno), regno);
- perror_with_name (mess);
- }
- }
- supply_register (regno, buf);
-}
+ tid = PIDGET (inferior_ptid); /* Not a threaded program. */
-/* Fetch register values from the inferior.
- If REGNO is negative, do this for all registers.
- Otherwise, REGNO specifies which register (so we can save time). */
+ errno = 0;
+ val = ptrace (PTRACE_PEEKUSER, tid, register_addr (regno, 0), 0);
+ if (errno != 0)
+ error ("Couldn't read register %s (#%d): %s.", REGISTER_NAME (regno),
+ regno, safe_strerror (errno));
-void
-old_fetch_inferior_registers (int regno)
-{
- if (regno >= 0)
- {
- fetch_register (regno);
- }
- else
- {
- for (regno = 0; regno < NUM_REGS; regno++)
- {
- fetch_register (regno);
- }
- }
+ supply_register (regno, &val);
}
-/* Registers we shouldn't try to store. */
-#define OLD_CANNOT_STORE_REGISTER(regno) ((regno) >= I386_NUM_GREGS)
-
/* Store one register. */
static void
store_register (int regno)
{
- /* This isn't really an address. But ptrace thinks of it as one. */
- CORE_ADDR regaddr;
- char mess[128]; /* For messages */
- register int i;
- unsigned int offset; /* Offset of registers within the u area. */
int tid;
+ int val;
- if (OLD_CANNOT_STORE_REGISTER (regno))
- {
- return;
- }
+ gdb_assert (!have_ptrace_getregs);
+ if (cannot_store_register (regno))
+ return;
- /* Overload thread id onto process id */
+ /* GNU/Linux LWP ID's are process ID's. */
if ((tid = TIDGET (inferior_ptid)) == 0)
- tid = PIDGET (inferior_ptid); /* no thread id, just use process id */
-
- offset = U_REGS_OFFSET;
-
- regaddr = register_addr (regno, offset);
- for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE))
- {
- errno = 0;
- ptrace (PT_WRITE_U, tid, (PTRACE_ARG3_TYPE) regaddr,
- *(PTRACE_XFER_TYPE *) & registers[REGISTER_BYTE (regno) + i]);
- regaddr += sizeof (PTRACE_XFER_TYPE);
- if (errno != 0)
- {
- sprintf (mess, "writing register %s (#%d)",
- REGISTER_NAME (regno), regno);
- perror_with_name (mess);
- }
- }
-}
-
-/* Store our register values back into the inferior.
- If REGNO is negative, do this for all registers.
- Otherwise, REGNO specifies which register (so we can save time). */
+ tid = PIDGET (inferior_ptid); /* Not a threaded program. */
-void
-old_store_inferior_registers (int regno)
-{
- if (regno >= 0)
- {
- store_register (regno);
- }
- else
- {
- for (regno = 0; regno < NUM_REGS; regno++)
- {
- store_register (regno);
- }
- }
+ errno = 0;
+ regcache_collect (regno, &val);
+ ptrace (PTRACE_POKEUSER, tid, register_addr (regno, 0), val);
+ if (errno != 0)
+ error ("Couldn't read register %s (#%d): %s.", REGISTER_NAME (regno),
+ regno, safe_strerror (errno));
}
@@ -573,16 +488,15 @@ static void dummy_sse_values (void) {}
int
cannot_fetch_register (int regno)
{
- if (! have_ptrace_getregs)
- return OLD_CANNOT_FETCH_REGISTER (regno);
- return 0;
+ gdb_assert (regno >= 0 && regno < NUM_REGS);
+ return (!have_ptrace_getregs && regmap[regno] == -1);
}
+
int
cannot_store_register (int regno)
{
- if (! have_ptrace_getregs)
- return OLD_CANNOT_STORE_REGISTER (regno);
- return 0;
+ gdb_assert (regno >= 0 && regno < NUM_REGS);
+ return (!have_ptrace_getregs && regmap[regno] == -1);
}
/* Fetch register REGNO from the child process. If REGNO is -1, do
@@ -596,9 +510,14 @@ fetch_inferior_registers (int regno)
/* Use the old method of peeking around in `struct user' if the
GETREGS request isn't available. */
- if (! have_ptrace_getregs)
+ if (!have_ptrace_getregs)
{
- old_fetch_inferior_registers (regno);
+ int i;
+
+ for (i = 0; i < NUM_REGS; i++)
+ if (regno == -1 || regno == i)
+ fetch_register (i);
+
return;
}
@@ -615,9 +534,9 @@ fetch_inferior_registers (int regno)
fetch_regs (tid);
/* The call above might reset `have_ptrace_getregs'. */
- if (! have_ptrace_getregs)
+ if (!have_ptrace_getregs)
{
- old_fetch_inferior_registers (-1);
+ fetch_inferior_registers (regno);
return;
}
@@ -662,9 +581,14 @@ store_inferior_registers (int regno)
/* Use the old method of poking around in `struct user' if the
SETREGS request isn't available. */
- if (! have_ptrace_getregs)
+ if (!have_ptrace_getregs)
{
- old_store_inferior_registers (regno);
+ int i;
+
+ for (i = 0; i < NUM_REGS; i++)
+ if (regno == -1 || regno == i)
+ store_register (i);
+
return;
}
@@ -724,7 +648,7 @@ i386_linux_dr_get (int regnum)
stuff to the target vectore. For now, just return zero if the
ptrace call fails. */
errno = 0;
- value = ptrace (PT_READ_U, tid,
+ value = ptrace (PTRACE_PEEKUSER, tid,
offsetof (struct user, u_debugreg[regnum]), 0);
if (errno != 0)
#if 0
@@ -747,7 +671,7 @@ i386_linux_dr_set (int regnum, unsigned
tid = PIDGET (inferior_ptid);
errno = 0;
- ptrace (PT_WRITE_U, tid,
+ ptrace (PTRACE_POKEUSER, tid,
offsetof (struct user, u_debugreg[regnum]), value);
if (errno != 0)
perror_with_name ("Couldn't write debug register");
Index: config/i386/nm-linux.h
===================================================================
RCS file: /cvs/src/src/gdb/config/i386/nm-linux.h,v
retrieving revision 1.18
diff -u -p -r1.18 nm-linux.h
--- config/i386/nm-linux.h 30 Jun 2002 18:43:06 -0000 1.18
+++ config/i386/nm-linux.h 9 Nov 2002 21:29:29 -0000
@@ -39,9 +39,6 @@ extern int kernel_u_size (void);
the core file of the register values. */
#define KERNEL_U_ADDR 0
-/* Offset of the registers within the user area. */
-#define U_REGS_OFFSET 0
-
extern CORE_ADDR register_u_addr (CORE_ADDR blockend, int regnum);
#define REGISTER_U_ADDR(addr, blockend, regnum) \
(addr) = register_u_addr (blockend, regnum)