Port libpulp to ppc64le

.github/workflows/coding-style.yml

@@ -15,7 +15,7 @@ jobs:
 
     steps:
     - name: dependencies
-      run: zypper -n install clang git findutils
+      run: zypper -n install clang git findutils file
     - uses: actions/checkout@v2
     - name: format
       run: find -type f \( -name "*.[c|h]" -or -name "*.cc" \) -exec clang-format -style=file -i {} \;

configure.ac

@@ -23,6 +23,9 @@ AC_INIT([libpulp],[0.3.6],[[email protected]])
 AC_CONFIG_AUX_DIR([config])
 AC_CONFIG_MACRO_DIRS([config])
 
+# For multiarch builds.
+AC_CANONICAL_TARGET
+
 # Check for the availability of macros from autoconf-archive.
 AC_MSG_CHECKING([autoconf-archive availability])
 m4_ifndef([AX_CHECK_COMPILE_FLAG], [ax_available="no"])
@@ -133,12 +136,6 @@ AX_PYTHON_MODULE([psutil], [fatal])
 AC_SUBST([AM_CFLAGS], ["-Wall -Wextra -Werror"])
 AC_SUBST([AM_CCASFLAGS], ["-Wa,--fatal-warnings"])
 
-# Use the glibc versions installed on path
-AC_ARG_WITH([glibc],
-AS_HELP_STRING([--with-glibc=GLIBC_PATH],[Use the glibc installed on GLIBC_PATH, where the .so file is present]),
-[AC_SUBST([AM_LDFLAGS], ["-Wl,--dynamic-linker=$with_glibc/ld-linux-x86-64.so.2 -Wl,--rpath=$with_glibc/"])],
-[])
-
 # Checking the call stack of all threads enables libpulp to only apply a live
 # patch when no threads sit within the target library.
 AC_ARG_ENABLE(stack-check,
@@ -220,18 +217,60 @@ AC_SUBST([PAGE_SIZE], [$($GETCONF PAGE_SIZE)]))
 # before the entry point, and the remaining nops after it. At running time,
 # whenever a live patch is applied, libpulp replaces the remaining nops with
 # instructions that redirect execution to the universe handling routines.
-AC_SUBST([ULP_NOPS_LEN], [16])
-AC_SUBST([PRE_NOPS_LEN], [14])
-
-AC_SUBST([ULP_NOPS_LEN_ENDBR64], [$(expr $ULP_NOPS_LEN + 4)])
-AC_SUBST([PRE_NOPS_LEN_ENDBR64], [$(expr $PRE_NOPS_LEN + 4)])
+_NOPS_LEN=0
+_PRE_NOPS_LEN=0
+
+_LD_LINUX=""
+AS_CASE([$target_cpu],
+        [x86_64],
+        [
+          _NOPS_LEN=16
+          _PRE_NOPS_LEN=14
+          _LD_LINUX="ld-linux-x86-64.so.2"
+          _PROC="x86_64"
+        ],
+        [powerpc64le],
+        [
+          _NOPS_LEN=17
+          _PRE_NOPS_LEN=16
+          _LD_LINUX="ld64.so.2"
+          _PROC="powerpc64le"
+        ]
+)
+
+AC_SUBST([ULP_NOPS_LEN], [$_NOPS_LEN])
+AC_SUBST([PRE_NOPS_LEN], [$_PRE_NOPS_LEN])
 
 AC_DEFINE_UNQUOTED([ULP_NOPS_LEN], [$ULP_NOPS_LEN],
 [Total number of padding nops])
 AC_DEFINE_UNQUOTED([PRE_NOPS_LEN], [$PRE_NOPS_LEN],
 [Padding nops before the entry point of functions])
-AC_DEFINE_UNQUOTED([ULP_NOPS_LEN_ENDBR64], [$ULP_NOPS_LEN_ENDBR64],
-[Total number of padding nops when endbr64 is issued])
+
+AC_DEFINE_UNQUOTED([LD_LINUX], ["$_LD_LINUX"],
+[Path to the ld-linux loader] )
+
+# Workaround a bug in autoconf 2.69
+AM_CONDITIONAL([CPU_X86_64],  [test "$_PROC" == "x86_64"])
+AM_CONDITIONAL([CPU_PPC64LE], [test "$_PROC" == "powerpc64le"])
+
+# Use the glibc versions installed on path
+AC_ARG_WITH([glibc],
+AS_HELP_STRING([--with-glibc=GLIBC_PATH],[Use the glibc installed on GLIBC_PATH, where the .so file is present]),
+[AC_SUBST([AM_LDFLAGS], ["-Wl,--dynamic-linker=$with_glibc/$_LD_LINUX -Wl,--rpath=$with_glibc/"])],
+[])
+
+# Check if -fpatchable-function-entry=$ULP_NOPS_LEN,$RE_NOPS_LEN works
+# correctly.
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
+  [[extern void g(void);
+    __attribute__((patchable_function_entry($_NOPS_LEN, $_PRE_NOPS_LEN)))
+    void f(void) { g(); }]])],
+  [patchable_works=yes],
+  [patchable_works=no])
+
+AS_IF([test "x$patchable_works" == "xno"],
+AC_MSG_ERROR(
+[The -fpatchable-functions-entry flag of your C compiler does not work correctly]))
 
 AC_CONFIG_FILES([Makefile
 		 include/Makefile

include/Makefile.am

@@ -27,3 +27,14 @@ noinst_HEADERS = \
 	terminal_colors.h \
 	ld_rtld.h \
 	insn_queue.h
+
+# Workaround a bug in Autoconf 2.69
+if CPU_X86_64
+noinst_HEADERS += \
+  arch/x86_64/arch_common.h
+endif
+
+if CPU_PPC64LE
+noinst_HEADERS += \
+  arch/powerpc64le/arch_common.h
+endif

include/arch/powerpc64le/arch_common.h

@@ -0,0 +1,34 @@
+#ifndef _ARCH_PPC64LE_H
+#define _ARCH_PPC64LE_H
+
+/** Offset of TLS pointer.  */
+#define TLS_DTV_OFFSET 0x8000
+
+/** Struct used to store the registers in memory.  */
+typedef struct pt_regs registers_t;
+
+/** Register in which the function stores the return value.  */
+#define FUNCTION_RETURN_REG(reg) ((reg).gpr[3])
+
+/** Register which acts as a program counter.  */
+#define PROGRAM_COUNTER_REG(reg) ((reg).nip)
+
+/** Register which acts as top of stack.  */
+#define STACK_TOP_REG(reg)       ((reg).gpr[1])
+
+/** Set the GLOBAL ENTRYPOINT REGISTER, which in power is r12.  */
+#define SET_GLOBAL_ENTRYPOINT_REG(reg, val) (reg).gpr[12] = (val)
+
+/* Program load bias, which can be recovered by running `ld --verbose`.  */
+#define EXECUTABLE_START         0x10000000UL
+
+/* The Red zone.  */
+#define RED_ZONE_LEN             512
+
+/**
+ * Number of bytes that the kernel subtracts from the program counter,
+ * when an ongoing syscall gets interrupted and must be restarted.
+ */
+#define RESTART_SYSCALL_SIZE     0
+
+#endif

include/arch/x86_64/arch_common.h

@@ -0,0 +1,37 @@
+#ifndef _ARCH_X86_64_H
+#define _ARCH_X86_64_H
+
+/** Intel endbr64 instruction optcode.  */
+#define INSN_ENDBR64 0xf3, 0x0f, 0x1e, 0xfa
+
+/** Offset of TLS pointer.  */
+#define TLS_DTV_OFFSET 0
+
+/** Struct used to store the registers in memory.  */
+typedef struct user_regs_struct registers_t;
+
+/** Register in which the function stores the return value.  */
+#define FUNCTION_RETURN_REG(reg) ((reg).rax)
+
+/** Register which acts as a program counter.  */
+#define PROGRAM_COUNTER_REG(reg) ((reg).rip)
+
+/** Register which acts as top of stack.  */
+#define STACK_TOP_REG(reg)       ((reg).rsp)
+
+/** Set the GLOBAL ENTRYPOINT REGISTER, which in x86_64 doesn't exist.  */
+#define SET_GLOBAL_ENTRYPOINT_REG(reg, val)
+
+/** Program load bias, which can be recovered by running `ld --verbose`.  */
+#define EXECUTABLE_START      0x400000UL
+
+/** The red zone.  */
+#define RED_ZONE_LEN          128
+
+/**
+ * Number of bytes that the kernel subtracts from the program counter,
+ * when an ongoing syscall gets interrupted and must be restarted.
+ */
+#define RESTART_SYSCALL_SIZE  2
+
+#endif

include/ulp.h

@@ -81,6 +81,8 @@ int __ulp_apply_patch();
 void __ulp_print();
 
 /* functions */
+void *memwrite(void *dest, const void *src, size_t n);
+
 void free_metadata(struct ulp_metadata *ulp);
 
 int unload_handlers(struct ulp_metadata *ulp);

include/ulp_common.h

@@ -35,7 +35,6 @@
  * scenarios.  */
 #define ULP_METADATA_BUF_LEN (512 * 1024)
 #define ULP_PATH_LEN 256
-#define RED_ZONE_LEN 128
 
 #define ARRAY_LENGTH(v) (sizeof(v) / sizeof(*(v)))
 

lib/Makefile.am

@@ -23,19 +23,37 @@ libpulp_la_SOURCES = \
   ulp.c \
   interpose.c \
   msg_queue.c \
-  error.c \
-  ulp_prologue.S \
-  ulp_interface.S
-libpulp_la_DEPENDENCIES= libpulp.versions
+  error.c
+
 libpulp_la_LDFLAGS = \
   -ldl \
-  -l:ld-linux-x86-64.so.2 \
   -Wl,--version-script=$(srcdir)/libpulp.versions \
   -Wl,--hash-style=sysv \ # Ubuntu seems to default to gnu, so be clear we ...
   $(AM_LDFLAGS) # ... want old style hash sections, else DT_HASH is empty.
 
+# Workaround a bug in Autoconf 2.69
+if CPU_X86_64
+libpulp_la_SOURCES += \
+  arch/x86_64/ulp_interface.S \
+  arch/x86_64/patch.c
+
+libpulp_la_LDFLAGS += \
+  -l:ld-linux-x86-64.so.2
+endif
+
+if CPU_PPC64LE
+libpulp_la_SOURCES += \
+  arch/powerpc64le/ulp_interface.S \
+  arch/powerpc64le/patch.c
+
+libpulp_la_LDFLAGS += \
+  -l:ld64.so.2
+endif
+
+libpulp_la_DEPENDENCIES= libpulp.versions
+
 libpulp_la_LIBADD = $(top_builddir)/common/libcommon.la
 
-AM_CFLAGS += -I$(top_srcdir)/include
+AM_CFLAGS += -I$(top_srcdir)/include -I$(top_srcdir)/include/arch/$(target_cpu)
 
 EXTRA_DIST = libpulp.versions