linux-user/ppc: Add vdso

Add support in gen-vdso-elfn.c.inc for the DT_PPC64_OPT
dynamic tag: this is an integer, so does not need relocation.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

linux-user/elfload.c

@@ -1187,6 +1187,14 @@ static void elf_core_copy_regs(target_elf_gregset_t *regs, const CPUPPCState *en
 #define USE_ELF_CORE_DUMP
 #define ELF_EXEC_PAGESIZE       4096
 
+#ifndef TARGET_PPC64
+# define VDSO_HEADER  "vdso-32.c.inc"
+#elif TARGET_BIG_ENDIAN
+# define VDSO_HEADER  "vdso-64.c.inc"
+#else
+# define VDSO_HEADER  "vdso-64le.c.inc"
+#endif
+
 #endif
 
 #ifdef TARGET_LOONGARCH64

linux-user/gen-vdso-elfn.c.inc

@@ -273,7 +273,14 @@ static void elfN(process)(FILE *outf, void *buf, bool need_bswap)
                 errors++;
                 break;
 
+            case PT_LOPROC + 3:
+                if (ehdr->e_machine == EM_PPC64) {
+                    break;  /* DT_PPC64_OPT: integer bitmask */
+                }
+                goto do_default;
+
             default:
+            do_default:
                 /* This is probably something target specific. */
                 fprintf(stderr, "VDSO has unknown DYNAMIC entry (%lx)\n",
                         (unsigned long)tag);

linux-user/ppc/Makefile.vdso

@@ -0,0 +1,20 @@
+include $(BUILD_DIR)/tests/tcg/ppc64-linux-user/config-target.mak
+
+SUBDIR = $(SRC_PATH)/linux-user/ppc
+VPATH += $(SUBDIR)
+
+all: $(SUBDIR)/vdso-32.so $(SUBDIR)/vdso-64.so $(SUBDIR)/vdso-64le.so
+
+LDFLAGS32 = -nostdlib -shared -Wl,-T,$(SUBDIR)/vdso-32.ld \
+            -Wl,-h,linux-vdso32.so.1 -Wl,--hash-style=both -Wl,--build-id=sha1
+LDFLAGS64 = -nostdlib -shared -Wl,-T,$(SUBDIR)/vdso-64.ld \
+            -Wl,-h,linux-vdso64.so.1 -Wl,--hash-style=both -Wl,--build-id=sha1
+
+$(SUBDIR)/vdso-32.so: vdso.S vdso-32.ld vdso-asmoffset.h
+	$(CC) -o $@ $(LDFLAGS32) -m32 $<
+
+$(SUBDIR)/vdso-64.so: vdso.S vdso-64.ld vdso-asmoffset.h
+	$(CC) -o $@ $(LDFLAGS64) -mbig-endian $<
+
+$(SUBDIR)/vdso-64le.so: vdso.S vdso-64.ld vdso-asmoffset.h
+	$(CC) -o $@ $(LDFLAGS64) -mlittle-endian $<

linux-user/ppc/meson.build

@@ -3,3 +3,15 @@ syscall_nr_generators += {
                    arguments: [ meson.current_source_dir() / 'syscallhdr.sh', '@INPUT@', '@OUTPUT@', '@EXTRA_ARGS@' ],
                    output: '@BASENAME@_nr.h')
 }
+
+vdso_32_inc = gen_vdso.process('vdso-32.so', extra_args: [
+                                   '-s', '__kernel_sigtramp32',
+                                   '-r', '__kernel_sigtramp_rt32'
+                               ])
+linux_user_ss.add(when: 'TARGET_PPC', if_true: vdso_32_inc)
+
+vdso_64_inc = gen_vdso.process('vdso-64.so',
+                               extra_args: ['-r', '__kernel_sigtramp_rt64'])
+vdso_64le_inc = gen_vdso.process('vdso-64le.so',
+                                 extra_args: ['-r', '__kernel_sigtramp_rt64'])
+linux_user_ss.add(when: 'TARGET_PPC64', if_true: [vdso_64_inc, vdso_64le_inc])

linux-user/ppc/signal.c

@@ -21,14 +21,7 @@
 #include "user-internals.h"
 #include "signal-common.h"
 #include "linux-user/trace.h"
-
-/* Size of dummy stack frame allocated when calling signal handler.
-   See arch/powerpc/include/asm/ptrace.h.  */
-#if defined(TARGET_PPC64)
-#define SIGNAL_FRAMESIZE 128
-#else
-#define SIGNAL_FRAMESIZE 64
-#endif
+#include "vdso-asmoffset.h"
 
 /* See arch/powerpc/include/asm/ucontext.h.  Only used for 32-bit PPC;
    on 64-bit PPC, sigcontext and mcontext are one and the same.  */
@@ -73,6 +66,16 @@ struct target_mcontext {
 #endif
 };
 
+QEMU_BUILD_BUG_ON(offsetof(struct target_mcontext, mc_fregs)
+                  != offsetof_mcontext_fregs);
+#if defined(TARGET_PPC64)
+QEMU_BUILD_BUG_ON(offsetof(struct target_mcontext, v_regs)
+                  != offsetof_mcontext_vregs_ptr);
+#else
+QEMU_BUILD_BUG_ON(offsetof(struct target_mcontext, mc_vregs)
+                  != offsetof_mcontext_vregs);
+#endif
+
 /* See arch/powerpc/include/asm/sigcontext.h.  */
 struct target_sigcontext {
     target_ulong _unused[4];
@@ -161,13 +164,18 @@ struct target_ucontext {
 #endif
 };
 
+#if !defined(TARGET_PPC64)
 /* See arch/powerpc/kernel/signal_32.c.  */
 struct target_sigframe {
     struct target_sigcontext sctx;
     struct target_mcontext mctx;
     int32_t abigap[56];
 };
 
+QEMU_BUILD_BUG_ON(offsetof(struct target_sigframe, mctx)
+                  != offsetof_sigframe_mcontext);
+#endif
+
 #if defined(TARGET_PPC64)
 
 #define TARGET_TRAMP_SIZE 6
@@ -184,6 +192,10 @@ struct target_rt_sigframe {
     char abigap[288];
 } __attribute__((aligned(16)));
 
+QEMU_BUILD_BUG_ON(offsetof(struct target_rt_sigframe,
+                           uc.tuc_sigcontext.mcontext)
+                  != offsetof_rt_sigframe_mcontext);
+
 #else
 
 struct target_rt_sigframe {
@@ -192,6 +204,9 @@ struct target_rt_sigframe {
     int32_t abigap[56];
 };
 
+QEMU_BUILD_BUG_ON(offsetof(struct target_rt_sigframe, uc.tuc_mcontext)
+                  != offsetof_rt_sigframe_mcontext);
+
 #endif
 
 #if defined(TARGET_PPC64)

linux-user/ppc/vdso-32.ld

@@ -0,0 +1,70 @@
+/*
+ * Linker script for linux powerpc64 replacement vdso.
+ *
+ * Copyright 2023 Linaro, Ltd.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+VERSION {
+        LINUX_2.6.15 {
+        global:
+                __kernel_gettimeofday;
+                __kernel_clock_gettime;
+                __kernel_clock_gettime64;
+                __kernel_clock_getres;
+                __kernel_time;
+                __kernel_sync_dicache;
+                __kernel_sigtramp32;
+                __kernel_sigtramp_rt32;
+                __kernel_getcpu;
+        local: *;
+        };
+}
+
+PHDRS {
+        phdr            PT_PHDR         FLAGS(4) PHDRS;
+        load            PT_LOAD         FLAGS(7) FILEHDR PHDRS; /* FLAGS=RWX */
+        dynamic         PT_DYNAMIC      FLAGS(4);
+        eh_frame_hdr    PT_GNU_EH_FRAME;
+        note            PT_NOTE         FLAGS(4);
+}
+
+SECTIONS {
+        . = SIZEOF_HEADERS;
+
+        /*
+         * The following, including the FILEHDRS and PHDRS, are modified
+         * when we relocate the binary.  We want them to be initially
+         * writable for the relocation; we'll force them read-only after.
+         */
+        .note           : { *(.note*) }         :load :note
+        .dynamic        : { *(.dynamic) }       :load :dynamic
+        .dynsym         : { *(.dynsym) }        :load
+        .data           : {
+                /*
+                 * There ought not be any real read-write data.
+                 * But since we manipulated the segment layout,
+                 * we have to put these sections somewhere.
+                 */
+                *(.data*)
+                *(.sdata*)
+                *(.got.plt) *(.got)
+                *(.gnu.linkonce.d.*)
+                *(.bss*)
+                *(.dynbss*)
+                *(.gnu.linkonce.b.*)
+        }
+
+        .rodata         : { *(.rodata*) }
+        .hash           : { *(.hash) }
+        .gnu.hash       : { *(.gnu.hash) }
+        .dynstr         : { *(.dynstr) }
+        .gnu.version    : { *(.gnu.version) }
+        .gnu.version_d  : { *(.gnu.version_d) }
+        .gnu.version_r  : { *(.gnu.version_r) }
+        .eh_frame_hdr   : { *(.eh_frame_hdr) }  :load :eh_frame_hdr
+        .eh_frame       : { *(.eh_frame) }      :load
+
+        .text           : { *(.text*) }         :load
+}

linux-user/ppc/vdso-64.ld

@@ -0,0 +1,68 @@
+/*
+ * Linker script for linux powerpc64 replacement vdso.
+ *
+ * Copyright 2023 Linaro, Ltd.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+VERSION {
+        LINUX_2.6.15 {
+        global:
+                __kernel_gettimeofday;
+                __kernel_clock_gettime;
+                __kernel_clock_getres;
+                __kernel_sync_dicache;
+                __kernel_sigtramp_rt64;
+                __kernel_getcpu;
+                __kernel_time;
+        local: *;
+        };
+}
+
+PHDRS {
+        phdr            PT_PHDR         FLAGS(4) PHDRS;
+        load            PT_LOAD         FLAGS(7) FILEHDR PHDRS; /* FLAGS=RWX */
+        dynamic         PT_DYNAMIC      FLAGS(4);
+        eh_frame_hdr    PT_GNU_EH_FRAME;
+        note            PT_NOTE         FLAGS(4);
+}
+
+SECTIONS {
+        . = SIZEOF_HEADERS;
+
+        /*
+         * The following, including the FILEHDRS and PHDRS, are modified
+         * when we relocate the binary.  We want them to be initially
+         * writable for the relocation; we'll force them read-only after.
+         */
+        .note           : { *(.note*) }         :load :note
+        .dynamic        : { *(.dynamic) }       :load :dynamic
+        .dynsym         : { *(.dynsym) }        :load
+        .data           : {
+                /*
+                 * There ought not be any real read-write data.
+                 * But since we manipulated the segment layout,
+                 * we have to put these sections somewhere.
+                 */
+                *(.data*)
+                *(.sdata*)
+                *(.got.plt) *(.got)
+                *(.gnu.linkonce.d.*)
+                *(.bss*)
+                *(.dynbss*)
+                *(.gnu.linkonce.b.*)
+        }
+
+        .rodata         : { *(.rodata*) }
+        .hash           : { *(.hash) }
+        .gnu.hash       : { *(.gnu.hash) }
+        .dynstr         : { *(.dynstr) }
+        .gnu.version    : { *(.gnu.version) }
+        .gnu.version_d  : { *(.gnu.version_d) }
+        .gnu.version_r  : { *(.gnu.version_r) }
+        .eh_frame_hdr   : { *(.eh_frame_hdr) }  :load :eh_frame_hdr
+        .eh_frame       : { *(.eh_frame) }      :load
+
+        .text           : { *(.text*) }         :load
+}

linux-user/ppc/vdso-asmoffset.h

@@ -0,0 +1,20 @@
+/*
+ * Size of dummy stack frame allocated when calling signal handler.
+ * See arch/powerpc/include/asm/ptrace.h.
+ */
+#ifdef TARGET_ABI32
+# define SIGNAL_FRAMESIZE                   64
+#else
+# define SIGNAL_FRAMESIZE                   128
+#endif
+
+#ifdef TARGET_ABI32
+# define offsetof_sigframe_mcontext         0x20
+# define offsetof_rt_sigframe_mcontext      0x140
+# define offsetof_mcontext_fregs            0xc0
+# define offsetof_mcontext_vregs            0x1d0
+#else
+# define offsetof_rt_sigframe_mcontext      0xe8
+# define offsetof_mcontext_fregs            0x180
+# define offsetof_mcontext_vregs_ptr        0x288
+#endif