[PATCH 3/8] UML - Fix missing x86_64 register definitions

From: Jeff Dike
Date: Mon Sep 25 2006 - 14:38:20 EST


The UML/x86_64 headers were missing ptrace support for some segment
registers. The underlying problem was that the x86_64 kernel uses
user_regs_struct rather than the ptrace register definitions in
ptrace. This patch switches UML/x86_64 to using user_regs_struct
for its definitions of the host's registers.

Signed-off-by: Jeff Dike <jdike@xxxxxxxxxxx>

Index: linux-2.6.18-mm/arch/um/include/sysdep-x86_64/ptrace.h
===================================================================
--- linux-2.6.18-mm.orig/arch/um/include/sysdep-x86_64/ptrace.h 2006-09-22 11:36:43.000000000 -0400
+++ linux-2.6.18-mm/arch/um/include/sysdep-x86_64/ptrace.h 2006-09-22 13:19:12.000000000 -0400
@@ -50,6 +50,21 @@
#define HOST_FS 25
#define HOST_GS 26

+/* Also defined in asm/ptrace-x86_64.h, but not in libc headers. So, these
+ * are already defined for kernel code, but not for userspace code.
+ */
+#ifndef FS_BASE
+/* These aren't defined in ptrace.h, but exist in struct user_regs_struct,
+ * which is what x86_64 ptrace actually uses.
+ */
+#define FS_BASE (HOST_FS_BASE * sizeof(long))
+#define GS_BASE (HOST_GS_BASE * sizeof(long))
+#define DS (HOST_DS * sizeof(long))
+#define ES (HOST_ES * sizeof(long))
+#define FS (HOST_FS * sizeof(long))
+#define GS (HOST_GS * sizeof(long))
+#endif
+
#define REGS_FS_BASE(r) ((r)[HOST_FS_BASE])
#define REGS_GS_BASE(r) ((r)[HOST_GS_BASE])
#define REGS_DS(r) ((r)[HOST_DS])
@@ -89,9 +104,12 @@ union uml_pt_regs {
#endif
#ifdef UML_CONFIG_MODE_SKAS
struct skas_regs {
- /* XXX */
- unsigned long regs[27];
- unsigned long fp[65];
+ /* x86_64 ptrace uses sizeof(user_regs_struct) as its register
+ * file size, while i386 uses FRAME_SIZE. Therefore, we need
+ * to use UM_FRAME_SIZE here instead of HOST_FRAME_SIZE.
+ */
+ unsigned long regs[UM_FRAME_SIZE];
+ unsigned long fp[HOST_FP_SIZE];
struct faultinfo faultinfo;
long syscall;
int is_user;
@@ -120,11 +138,16 @@ extern int mode_tt;
#define UPT_R14(r) __CHOOSE_MODE(SC_R14(UPT_SC(r)), REGS_R14((r)->skas.regs))
#define UPT_R15(r) __CHOOSE_MODE(SC_R15(UPT_SC(r)), REGS_R15((r)->skas.regs))
#define UPT_CS(r) __CHOOSE_MODE(SC_CS(UPT_SC(r)), REGS_CS((r)->skas.regs))
+#define UPT_FS_BASE(r) \
+ __CHOOSE_MODE(SC_FS_BASE(UPT_SC(r)), REGS_FS_BASE((r)->skas.regs))
#define UPT_FS(r) __CHOOSE_MODE(SC_FS(UPT_SC(r)), REGS_FS((r)->skas.regs))
+#define UPT_GS_BASE(r) \
+ __CHOOSE_MODE(SC_GS_BASE(UPT_SC(r)), REGS_GS_BASE((r)->skas.regs))
#define UPT_GS(r) __CHOOSE_MODE(SC_GS(UPT_SC(r)), REGS_GS((r)->skas.regs))
#define UPT_DS(r) __CHOOSE_MODE(SC_DS(UPT_SC(r)), REGS_DS((r)->skas.regs))
#define UPT_ES(r) __CHOOSE_MODE(SC_ES(UPT_SC(r)), REGS_ES((r)->skas.regs))
#define UPT_CS(r) __CHOOSE_MODE(SC_CS(UPT_SC(r)), REGS_CS((r)->skas.regs))
+#define UPT_SS(r) __CHOOSE_MODE(SC_SS(UPT_SC(r)), REGS_SS((r)->skas.regs))
#define UPT_ORIG_RAX(r) \
__CHOOSE_MODE((r)->tt.orig_rax, REGS_ORIG_RAX((r)->skas.regs))

@@ -183,6 +206,13 @@ struct syscall_args {
case RBP: val = UPT_RBP(regs); break; \
case ORIG_RAX: val = UPT_ORIG_RAX(regs); break; \
case CS: val = UPT_CS(regs); break; \
+ case SS: val = UPT_SS(regs); break; \
+ case FS_BASE: val = UPT_FS_BASE(regs); break; \
+ case GS_BASE: val = UPT_GS_BASE(regs); break; \
+ case DS: val = UPT_DS(regs); break; \
+ case ES: val = UPT_ES(regs); break; \
+ case FS : val = UPT_FS (regs); break; \
+ case GS: val = UPT_GS(regs); break; \
case EFLAGS: val = UPT_EFLAGS(regs); break; \
default : \
panic("Bad register in UPT_REG : %d\n", reg); \
@@ -214,6 +244,13 @@ struct syscall_args {
case RBP: UPT_RBP(regs) = __upt_val; break; \
case ORIG_RAX: UPT_ORIG_RAX(regs) = __upt_val; break; \
case CS: UPT_CS(regs) = __upt_val; break; \
+ case SS: UPT_SS(regs) = __upt_val; break; \
+ case FS_BASE: UPT_FS_BASE(regs) = __upt_val; break; \
+ case GS_BASE: UPT_GS_BASE(regs) = __upt_val; break; \
+ case DS: UPT_DS(regs) = __upt_val; break; \
+ case ES: UPT_ES(regs) = __upt_val; break; \
+ case FS: UPT_FS(regs) = __upt_val; break; \
+ case GS: UPT_GS(regs) = __upt_val; break; \
case EFLAGS: UPT_EFLAGS(regs) = __upt_val; break; \
default : \
panic("Bad register in UPT_SET : %d\n", reg); \
Index: linux-2.6.18-mm/arch/um/include/sysdep-x86_64/sc.h
===================================================================
--- linux-2.6.18-mm.orig/arch/um/include/sysdep-x86_64/sc.h 2006-06-17 21:49:35.000000000 -0400
+++ linux-2.6.18-mm/arch/um/include/sysdep-x86_64/sc.h 2006-09-22 13:19:12.000000000 -0400
@@ -35,11 +35,11 @@
#define SC_GS(sc) SC_OFFSET(sc, SC_GS)
#define SC_EFLAGS(sc) SC_OFFSET(sc, SC_EFLAGS)
#define SC_SIGMASK(sc) SC_OFFSET(sc, SC_SIGMASK)
+#define SC_SS(sc) SC_OFFSET(sc, SC_SS)
#if 0
#define SC_ORIG_RAX(sc) SC_OFFSET(sc, SC_ORIG_RAX)
#define SC_DS(sc) SC_OFFSET(sc, SC_DS)
#define SC_ES(sc) SC_OFFSET(sc, SC_ES)
-#define SC_SS(sc) SC_OFFSET(sc, SC_SS)
#endif

#endif
Index: linux-2.6.18-mm/include/asm-um/ptrace-x86_64.h
===================================================================
--- linux-2.6.18-mm.orig/include/asm-um/ptrace-x86_64.h 2006-09-22 11:34:59.000000000 -0400
+++ linux-2.6.18-mm/include/asm-um/ptrace-x86_64.h 2006-09-22 13:19:12.000000000 -0400
@@ -16,12 +16,15 @@

#define HOST_AUDIT_ARCH AUDIT_ARCH_X86_64

+/* Also defined in sysdep/ptrace.h, so may already be defined. */
+#ifndef FS_BASE
#define FS_BASE (21 * sizeof(unsigned long))
#define GS_BASE (22 * sizeof(unsigned long))
#define DS (23 * sizeof(unsigned long))
#define ES (24 * sizeof(unsigned long))
#define FS (25 * sizeof(unsigned long))
#define GS (26 * sizeof(unsigned long))
+#endif

#define PT_REGS_RBX(r) UPT_RBX(&(r)->regs)
#define PT_REGS_RCX(r) UPT_RCX(&(r)->regs)

-
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