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Re: [PATCH]: Fix syscall restart handling on sparc*-linux
From: Mark Kettenis <mark.kettenis@xs4all.nl>
Date: Sun, 11 May 2008 22:33:34 +0200 (CEST)
> > Date: Sun, 11 May 2008 13:18:50 -0700 (PDT)
> > From: David Miller <davem@davemloft.net>
> >
> > The write_pc target method simply clears the bit, which does nothing
> > on previous kernels, but cancels syscall restart on newer kernels.
> >
> > This fixes 40 or so testsuite failures.
> >
> > Ok to commit?
>
> I wouldn't mind a #define for these bits. Otherwise, it looks fine to me.
Done, and installed as follows:
2008-05-11 David S. Miller <davem@davemloft.net>
* sparc-linux-tdep.c (PSR_SYSCALL): Define.
(sparc_linux_write_pc): New function.
(sparc32_linux_init_abi): Register it.
* sparc64-linux-tdep.c (TSTATE_SYSCALL): Define.
(sparc64_linux_write_pc): New function.
(sparc64_linux_init_abi): Register it.
Index: gdb/sparc-linux-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/sparc-linux-tdep.c,v
retrieving revision 1.26
diff -u -r1.26 sparc-linux-tdep.c
--- gdb/sparc-linux-tdep.c 11 May 2008 20:03:25 -0000 1.26
+++ gdb/sparc-linux-tdep.c 11 May 2008 22:09:09 -0000
@@ -211,6 +211,32 @@
sparc32_collect_fpregset (regcache, regnum, fpregs);
}
+/* Set the program counter for process PTID to PC. */
+
+#define PSR_SYSCALL 0x00004000
+
+static void
+sparc_linux_write_pc (struct regcache *regcache, CORE_ADDR pc)
+{
+ struct gdbarch_tdep *tdep = gdbarch_tdep (get_regcache_arch (regcache));
+ ULONGEST psr;
+
+ regcache_cooked_write_unsigned (regcache, tdep->pc_regnum, pc);
+ regcache_cooked_write_unsigned (regcache, tdep->npc_regnum, pc + 4);
+
+ /* Clear the "in syscall" bit to prevent the kernel from
+ messing with the PCs we just installed, if we happen to be
+ within an interrupted system call that the kernel wants to
+ restart.
+
+ Note that after we return from the dummy call, the PSR et al.
+ registers will be automatically restored, and the kernel
+ continues to restart the system call at this point. */
+ regcache_cooked_read_unsigned (regcache, SPARC32_PSR_REGNUM, &psr);
+ psr &= ~PSR_SYSCALL;
+ regcache_cooked_write_unsigned (regcache, SPARC32_PSR_REGNUM, psr);
+}
+
static void
@@ -251,6 +277,8 @@
/* Hook in the DWARF CFI frame unwinder. */
dwarf2_append_unwinders (gdbarch);
+
+ set_gdbarch_write_pc (gdbarch, sparc_linux_write_pc);
}
/* Provide a prototype to silence -Wmissing-prototypes. */
Index: gdb/sparc64-linux-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/sparc64-linux-tdep.c,v
retrieving revision 1.20
diff -u -r1.20 sparc64-linux-tdep.c
--- gdb/sparc64-linux-tdep.c 11 May 2008 20:03:26 -0000 1.20
+++ gdb/sparc64-linux-tdep.c 11 May 2008 22:09:09 -0000
@@ -174,6 +174,32 @@
sparc64_collect_fpregset (regcache, regnum, fpregs);
}
+/* Set the program counter for process PTID to PC. */
+
+#define TSTATE_SYSCALL 0x0000000000000020ULL
+
+static void
+sparc64_linux_write_pc (struct regcache *regcache, CORE_ADDR pc)
+{
+ struct gdbarch_tdep *tdep = gdbarch_tdep (get_regcache_arch (regcache));
+ ULONGEST state;
+
+ regcache_cooked_write_unsigned (regcache, tdep->pc_regnum, pc);
+ regcache_cooked_write_unsigned (regcache, tdep->npc_regnum, pc + 4);
+
+ /* Clear the "in syscall" bit to prevent the kernel from
+ messing with the PCs we just installed, if we happen to be
+ within an interrupted system call that the kernel wants to
+ restart.
+
+ Note that after we return from the dummy call, the TSTATE et al.
+ registers will be automatically restored, and the kernel
+ continues to restart the system call at this point. */
+ regcache_cooked_read_unsigned (regcache, SPARC64_STATE_REGNUM, &state);
+ state &= ~TSTATE_SYSCALL;
+ regcache_cooked_write_unsigned (regcache, SPARC64_STATE_REGNUM, state);
+}
+
static void
@@ -211,6 +237,8 @@
/* Make sure we can single-step over signal return system calls. */
tdep->step_trap = sparc64_linux_step_trap;
+
+ set_gdbarch_write_pc (gdbarch, sparc64_linux_write_pc);
}