Merge tag 'pull-lu-20231030' of https://gitlab.com/rth7680/qemu into …

…staging linux-user: Fix guest signal remapping after adjusting SIGABRT linux-user: Implement VDSOs * tag 'pull-lu-20231030' of https://gitlab.com/rth7680/qemu: (21 commits) build: Add update-linux-vdso makefile rule linux-user: Show vdso address in /proc/pid/maps linux-user/s390x: Add vdso linux-user/s390x: Rename __SIGNAL_FRAMESIZE to STACK_FRAME_OVERHEAD linux-user/ppc: Add vdso linux-user/loongarch64: Add vdso linux-user/riscv: Add vdso linux-user/hppa: Add vdso linux-user/arm: Add vdso linux-user/aarch64: Add vdso linux-user/x86_64: Add vdso linux-user/i386: Add vdso linux-user: Add gen-vdso tool linux-user: Load vdso image if available linux-user: Replace bprm->fd with bprm->src.fd linux-user: Use ImageSource in load_symbols linux-user: Use ImageSource in load_elf_image linux-user: Do not clobber bprm_buf swapping ehdr linux-user: Tidy loader_exec linux-user: Introduce imgsrc_read, imgsrc_read_alloc ... Conflicts: linux-user/arm/signal.c Fix an #include context conflict. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
qemu · Oct 30, 2023 · 516fffc · 516fffc
2 parents 235fe6d + 335b8f7
commit 516fffc
Show file tree

Hide file tree

Showing 76 changed files with 3,278 additions and 211 deletions.
diff --git a/Makefile b/Makefile
@@ -283,6 +283,13 @@ include $(SRC_PATH)/tests/vm/Makefile.include
 print-help-run = printf "  %-30s - %s\\n" "$1" "$2"
 print-help = @$(call print-help-run,$1,$2)
 
+.PHONY: update-linux-vdso
+update-linux-vdso:
+	@for m in $(SRC_PATH)/linux-user/*/Makefile.vdso; do \
+	  $(MAKE) $(SUBDIR_MAKEFLAGS) -C $$(dirname $$m) -f Makefile.vdso \
+		SRC_PATH=$(SRC_PATH) BUILD_DIR=$(BUILD_DIR); \
+	done
+
 .PHONY: help
 help:
 	@echo  'Generic targets:'
@@ -303,6 +310,9 @@ endif
 	$(call print-help,distclean,Remove all generated files)
 	$(call print-help,dist,Build a distributable tarball)
 	@echo  ''
+	@echo  'Linux-user targets:'
+	$(call print-help,update-linux-vdso,Build linux-user vdso images)
+	@echo  ''
 	@echo  'Test targets:'
 	$(call print-help,check,Run all tests (check-help for details))
 	$(call print-help,bench,Run all benchmarks)

diff --git a/linux-user/aarch64/Makefile.vdso b/linux-user/aarch64/Makefile.vdso
@@ -0,0 +1,15 @@
+include $(BUILD_DIR)/tests/tcg/aarch64-linux-user/config-target.mak
+
+SUBDIR = $(SRC_PATH)/linux-user/aarch64
+VPATH += $(SUBDIR)
+
+all: $(SUBDIR)/vdso-be.so $(SUBDIR)/vdso-le.so
+
+LDFLAGS = -nostdlib -shared -Wl,-h,linux-vdso.so.1 -Wl,--build-id=sha1 \
+	  -Wl,--hash-style=both -Wl,-T,$(SUBDIR)/vdso.ld
+
+$(SUBDIR)/vdso-be.so: vdso.S vdso.ld
+	$(CC) -o $@ $(LDFLAGS) -mbig-endian $<
+
+$(SUBDIR)/vdso-le.so: vdso.S vdso.ld
+	$(CC) -o $@ $(LDFLAGS) -mlittle-endian $<
diff --git a/linux-user/aarch64/meson.build b/linux-user/aarch64/meson.build
@@ -0,0 +1,11 @@
+# TARGET_BIG_ENDIAN is defined to 'n' for little-endian; which means it
+# is always true as far as source_set.apply() is concerned.  Always build
+# both header files and include the right one via #if.
+
+vdso_be_inc = gen_vdso.process('vdso-be.so',
+                               extra_args: ['-r', '__kernel_rt_sigreturn'])
+
+vdso_le_inc = gen_vdso.process('vdso-le.so',
+                               extra_args: ['-r', '__kernel_rt_sigreturn'])
+
+linux_user_ss.add(when: 'TARGET_AARCH64', if_true: [vdso_be_inc, vdso_le_inc])
diff --git a/linux-user/aarch64/vdso-be.so b/linux-user/aarch64/vdso-be.so
diff --git a/linux-user/aarch64/vdso-le.so b/linux-user/aarch64/vdso-le.so
diff --git a/linux-user/aarch64/vdso.S b/linux-user/aarch64/vdso.S
@@ -0,0 +1,71 @@
+/*
+ * aarch64 linux replacement vdso.
+ *
+ * Copyright 2023 Linaro, Ltd.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include <asm/unistd.h>
+
+/* ??? These are in include/elf.h, which is not ready for inclusion in asm. */
+#define NT_GNU_PROPERTY_TYPE_0  5
+#define GNU_PROPERTY_AARCH64_FEATURE_1_AND      0xc0000000
+#define GNU_PROPERTY_AARCH64_FEATURE_1_BTI      (1U << 0)
+#define GNU_PROPERTY_AARCH64_FEATURE_1_PAC      (1U << 1)
+
+#define GNU_PROPERTY_AARCH64_FEATURE_1_DEFAULT \
+    (GNU_PROPERTY_AARCH64_FEATURE_1_BTI | GNU_PROPERTY_AARCH64_FEATURE_1_PAC)
+
+	.section .note.gnu.property
+	.align	3
+	.long	2f - 1f
+	.long	6f - 3f
+	.long	NT_GNU_PROPERTY_TYPE_0
+1:	.string	"GNU"
+2:	.align	3
+3:	.long	GNU_PROPERTY_AARCH64_FEATURE_1_AND
+	.long	5f - 4f
+4:	.long	GNU_PROPERTY_AARCH64_FEATURE_1_DEFAULT
+5:	.align	3
+6:
+
+	.text
+
+.macro endf name
+	.globl	\name
+	.type	\name, @function
+	.size	\name, . - \name
+.endm
+
+.macro vdso_syscall name, nr
+\name:
+	bti	c
+	mov	x8, #\nr
+	svc	#0
+	ret
+endf	\name
+.endm
+
+	.cfi_startproc
+
+vdso_syscall __kernel_gettimeofday, __NR_gettimeofday
+vdso_syscall __kernel_clock_gettime, __NR_clock_gettime
+vdso_syscall __kernel_clock_getres, __NR_clock_getres
+
+	.cfi_endproc
+
+
+/*
+ * TODO: The kernel makes a big deal of turning off the .cfi directives,
+ * because they cause libgcc to crash, but that's because they're wrong.
+ *
+ * For now, elide the unwind info for __kernel_rt_sigreturn and rely on
+ * the libgcc fallback routine as we have always done.  This requires
+ * that the code sequence used be exact.
+ */
+__kernel_rt_sigreturn:
+	/* No BTI C insn here -- we arrive via RET. */
+	mov	x8, #__NR_rt_sigreturn
+	svc	#0
+endf	__kernel_rt_sigreturn
diff --git a/linux-user/aarch64/vdso.ld b/linux-user/aarch64/vdso.ld
@@ -0,0 +1,72 @@
+/*
+ * Linker script for linux aarch64 replacement vdso.
+ *
+ * Copyright 2021 Linaro, Ltd.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+VERSION {
+        LINUX_2.6.39 {
+        global:
+                __kernel_rt_sigreturn;
+                __kernel_gettimeofday;
+                __kernel_clock_gettime;
+                __kernel_clock_getres;
+
+        local: *;
+        };
+}
+
+
+PHDRS {
+        phdr            PT_PHDR         FLAGS(4) PHDRS;
+        load            PT_LOAD         FLAGS(7) FILEHDR PHDRS;
+        dynamic         PT_DYNAMIC      FLAGS(4);
+        eh_frame_hdr    PT_GNU_EH_FRAME;
+        note            PT_NOTE         FLAGS(4);
+}
+
+SECTIONS {
+        /*
+         * We can't prelink to any address without knowing something about
+         * the virtual memory space of the host, since that leaks over into
+         * the available memory space of the guest.
+         */
+        . = 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
+        /*
+         * There ought not be any real read-write data.
+         * But since we manipulated the segment layout,
+         * we have to put these sections somewhere.
+         */
+        .data           : {
+                *(.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   =0xd503201f
+}
diff --git a/linux-user/arm/Makefile.vdso b/linux-user/arm/Makefile.vdso
@@ -0,0 +1,17 @@
+include $(BUILD_DIR)/tests/tcg/arm-linux-user/config-target.mak
+
+SUBDIR = $(SRC_PATH)/linux-user/arm
+VPATH += $(SUBDIR)
+
+all: $(SUBDIR)/vdso-be.so $(SUBDIR)/vdso-le.so
+
+# Adding -use-blx disables unneeded interworking without actually using blx.
+LDFLAGS = -nostdlib -shared -Wl,-use-blx \
+	  -Wl,-h,linux-vdso.so.1 -Wl,--build-id=sha1 \
+	  -Wl,--hash-style=both -Wl,-T,$(SUBDIR)/vdso.ld
+
+$(SUBDIR)/vdso-be.so: vdso.S vdso.ld vdso-asmoffset.h
+	$(CC) -o $@ $(LDFLAGS) -mbig-endian $<
+
+$(SUBDIR)/vdso-le.so: vdso.S vdso.ld vdso-asmoffset.h
+	$(CC) -o $@ $(LDFLAGS) -mlittle-endian $<
diff --git a/linux-user/arm/meson.build b/linux-user/arm/meson.build
@@ -5,3 +5,15 @@ syscall_nr_generators += {
                    arguments: [ meson.current_source_dir() / 'syscallhdr.sh', '@INPUT@', '@OUTPUT@', '@EXTRA_ARGS@' ],
                    output: '@BASENAME@_nr.h')
 }
+
+# TARGET_BIG_ENDIAN is defined to 'n' for little-endian; which means it
+# is always true as far as source_set.apply() is concerned.  Always build
+# both header files and include the right one via #if.
+
+vdso_be_inc = gen_vdso.process('vdso-be.so',
+                               extra_args: ['-s', 'sigreturn_codes'])
+
+vdso_le_inc = gen_vdso.process('vdso-le.so',
+                               extra_args: ['-s', 'sigreturn_codes'])
+
+linux_user_ss.add(when: 'TARGET_ARM', if_true: [vdso_be_inc, vdso_le_inc])
diff --git a/linux-user/arm/signal.c b/linux-user/arm/signal.c
@@ -22,6 +22,7 @@
 #include "signal-common.h"
 #include "linux-user/trace.h"
 #include "target/arm/cpu-features.h"
+#include "vdso-asmoffset.h"
 
 struct target_sigcontext {
     abi_ulong trap_no;
@@ -103,6 +104,11 @@ struct rt_sigframe
     struct sigframe sig;
 };
 
+QEMU_BUILD_BUG_ON(offsetof(struct sigframe, retcode[3])
+                  != SIGFRAME_RC3_OFFSET);
+QEMU_BUILD_BUG_ON(offsetof(struct rt_sigframe, sig.retcode[3])
+                  != RT_SIGFRAME_RC3_OFFSET);
+
 static abi_ptr sigreturn_fdpic_tramp;
 
 /*
@@ -161,16 +167,19 @@ get_sigframe(struct target_sigaction *ka, CPUARMState *regs, int framesize)
     return (sp - framesize) & ~7;
 }
 
+static void write_arm_sigreturn(uint32_t *rc, int syscall);
+static void write_arm_fdpic_sigreturn(uint32_t *rc, int ofs);
+
 static int
 setup_return(CPUARMState *env, struct target_sigaction *ka, int usig,
              struct sigframe *frame, abi_ulong sp_addr)
 {
     abi_ulong handler = 0;
     abi_ulong handler_fdpic_GOT = 0;
     abi_ulong retcode;
-    int thumb, retcode_idx;
-    int is_fdpic = info_is_fdpic(((TaskState *)thread_cpu->opaque)->info);
-    bool copy_retcode;
+    bool is_fdpic = info_is_fdpic(((TaskState *)thread_cpu->opaque)->info);
+    bool is_rt = ka->sa_flags & TARGET_SA_SIGINFO;
+    bool thumb;
 
     if (is_fdpic) {
         /* In FDPIC mode, ka->_sa_handler points to a function
@@ -185,9 +194,7 @@ setup_return(CPUARMState *env, struct target_sigaction *ka, int usig,
     } else {
         handler = ka->_sa_handler;
     }
-
     thumb = handler & 1;
-    retcode_idx = thumb + (ka->sa_flags & TARGET_SA_SIGINFO ? 2 : 0);
 
     uint32_t cpsr = cpsr_read(env);
 
@@ -203,24 +210,32 @@ setup_return(CPUARMState *env, struct target_sigaction *ka, int usig,
         cpsr &= ~CPSR_E;
     }
 
+    /* Our vdso default_sigreturn label is a table of entry points. */
+    retcode = default_sigreturn + (is_fdpic * 2 + is_rt) * 8;
+
+    /*
+     * Put the sigreturn code on the stack no matter which return
+     * mechanism we use in order to remain ABI compliant.
+     * Because this is about ABI, always use the A32 instructions,
+     * despite the fact that our actual vdso trampoline is T16.
+     */
+    if (is_fdpic) {
+        write_arm_fdpic_sigreturn(frame->retcode,
+                                  is_rt ? RT_SIGFRAME_RC3_OFFSET
+                                        : SIGFRAME_RC3_OFFSET);
+    } else {
+        write_arm_sigreturn(frame->retcode,
+                            is_rt ? TARGET_NR_rt_sigreturn
+                                  : TARGET_NR_sigreturn);
+    }
+
     if (ka->sa_flags & TARGET_SA_RESTORER) {
         if (is_fdpic) {
+            /* Place the function descriptor in slot 3. */
             __put_user((abi_ulong)ka->sa_restorer, &frame->retcode[3]);
-            retcode = (sigreturn_fdpic_tramp +
-                       retcode_idx * RETCODE_BYTES + thumb);
-            copy_retcode = true;
         } else {
             retcode = ka->sa_restorer;
-            copy_retcode = false;
         }
-    } else {
-        retcode = default_sigreturn + retcode_idx * RETCODE_BYTES + thumb;
-        copy_retcode = true;
-    }
-
-    /* Copy the code to the stack slot for ABI compatibility. */
-    if (copy_retcode) {
-        memcpy(frame->retcode, g2h_untagged(retcode & ~1), RETCODE_BYTES);
     }
 
     env->regs[0] = usig;

diff --git a/linux-user/arm/vdso-asmoffset.h b/linux-user/arm/vdso-asmoffset.h
@@ -0,0 +1,3 @@
+/* offsetof(struct sigframe, retcode[3]) */
+#define SIGFRAME_RC3_OFFSET     756
+#define RT_SIGFRAME_RC3_OFFSET  884
diff --git a/linux-user/arm/vdso-be.so b/linux-user/arm/vdso-be.so
diff --git a/linux-user/arm/vdso-le.so b/linux-user/arm/vdso-le.so