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linux-user/arm: Add vdso 

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2021-07-06 09:55:12 -07:00
parent ee95fae075
commit a9f495b93f
9 changed files with 310 additions and 21 deletions
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17
linux-user/arm/Makefile.vdso Normal file
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@ -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 $<

12
linux-user/arm/meson.build
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@ -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])

55
linux-user/arm/signal.c
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@ -21,6 +21,7 @@
#include "user-internals.h"
#include "signal-common.h"
#include "linux-user/trace.h"
#include "vdso-asmoffset.h"
struct target_sigcontext {
abi_ulong trap_no;
@ -102,6 +103,11 @@ 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;
/*
@ -160,6 +166,9 @@ 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)
@ -167,9 +176,9 @@ setup_return(CPUARMState *env, struct target_sigaction *ka, int usig,
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
@ -184,9 +193,7 @@ 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);
@ -202,24 +209,32 @@ setup_return(CPUARMState *env, struct target_sigaction *ka, int usig,
cpsr &= ~CPSR_E;
}
if (ka->sa_flags & TARGET_SA_RESTORER) {
if (is_fdpic) {
__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;
}
/* 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 {
retcode = default_sigreturn + retcode_idx * RETCODE_BYTES + thumb;
copy_retcode = true;
write_arm_sigreturn(frame->retcode,
is_rt ? TARGET_NR_rt_sigreturn
: TARGET_NR_sigreturn);
}
/* Copy the code to the stack slot for ABI compatibility. */
if (copy_retcode) {
memcpy(frame->retcode, g2h_untagged(retcode & ~1), RETCODE_BYTES);
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]);
} else {
retcode = ka->sa_restorer;
}
}
env->regs[0] = usig;

3
linux-user/arm/vdso-asmoffset.h Normal file
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@ -0,0 +1,3 @@
/* offsetof(struct sigframe, retcode[3]) */
#define SIGFRAME_RC3_OFFSET 756
#define RT_SIGFRAME_RC3_OFFSET 884

BIN
linux-user/arm/vdso-be.so Executable file
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Binary file not shown.

BIN
linux-user/arm/vdso-le.so Executable file
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Binary file not shown.

174
linux-user/arm/vdso.S Normal file
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@ -0,0 +1,174 @@
/*
* arm linux replacement vdso.
*
* Copyright 2023 Linaro, Ltd.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include <asm/unistd.h>
#include "vdso-asmoffset.h"
/*
* All supported cpus have T16 instructions: at least arm4t.
*
* We support user-user with m-profile cpus as an extension, because it
* is useful for testing gcc, which requires we avoid A32 instructions.
*/
.thumb
.arch armv4t
.eabi_attribute Tag_FP_arch, 0
.eabi_attribute Tag_ARM_ISA_use, 0
.text
.macro raw_syscall n
.ifne \n < 0x100
mov r7, #\n
.elseif \n < 0x1ff
mov r7, #0xff
add r7, #(\n - 0xff)
.else
.err
.endif
swi #0
.endm
.macro fdpic_thunk ofs
ldr r3, [sp, #\ofs]
ldmia r2, {r2, r3}
mov r9, r3
bx r2
.endm
.macro endf name
.globl \name
.type \name, %function
.size \name, . - \name
.endm
/*
* We must save/restore r7 for the EABI syscall number.
* While we're doing that, we might as well save LR to get a free return,
* and a branch that is interworking back to ARMv5.
*/
.macro SYSCALL name, nr
\name:
.cfi_startproc
push {r7, lr}
.cfi_adjust_cfa_offset 8
.cfi_offset r7, -8
.cfi_offset lr, -4
raw_syscall \nr
pop {r7, pc}
.cfi_endproc
endf \name
.endm
SYSCALL __vdso_clock_gettime, __NR_clock_gettime
SYSCALL __vdso_clock_gettime64, __NR_clock_gettime64
SYSCALL __vdso_clock_getres, __NR_clock_getres
SYSCALL __vdso_gettimeofday, __NR_gettimeofday
/*
* We, like the real kernel, use a table of sigreturn trampolines.
* Unlike the real kernel, we do not attempt to pack this into as
* few bytes as possible -- simply use 8 bytes per slot.
*
* Within each slot, use the exact same code sequence as the kernel,
* lest we trip up someone doing code inspection.
*/
.macro slot n
.balign 8
.org sigreturn_codes + 8 * \n
.endm
.macro cfi_fdpic_r9 ofs
/*
* fd = *(r13 + ofs)
* r9 = *(fd + 4)
*
* DW_CFA_expression r9, length (7),
* DW_OP_breg13, ofs, DW_OP_deref,
* DW_OP_plus_uconst, 4, DW_OP_deref
*/
.cfi_escape 0x10, 9, 7, 0x7d, (\ofs & 0x7f) + 0x80, (\ofs >> 7), 0x06, 0x23, 4, 0x06
.endm
.macro cfi_fdpic_pc ofs
/*
* fd = *(r13 + ofs)
* pc = *fd
*
* DW_CFA_expression lr (14), length (5),
* DW_OP_breg13, ofs, DW_OP_deref, DW_OP_deref
*/
.cfi_escape 0x10, 14, 5, 0x7d, (\ofs & 0x7f) + 0x80, (\ofs >> 7), 0x06, 0x06
.endm
/*
* Start the unwind info at least one instruction before the signal
* trampoline, because the unwinder will assume we are returning
* after a call site.
*/
.cfi_startproc simple
.cfi_signal_frame
.cfi_return_column 15
.cfi_def_cfa sp, 32 + 64
.cfi_offset r0, -16 * 4
.cfi_offset r1, -15 * 4
.cfi_offset r2, -14 * 4
.cfi_offset r3, -13 * 4
.cfi_offset r4, -12 * 4
.cfi_offset r5, -11 * 4
.cfi_offset r6, -10 * 4
.cfi_offset r7, -9 * 4
.cfi_offset r8, -8 * 4
.cfi_offset r9, -7 * 4
.cfi_offset r10, -6 * 4
.cfi_offset r11, -5 * 4
.cfi_offset r12, -4 * 4
.cfi_offset r13, -3 * 4
.cfi_offset r14, -2 * 4
.cfi_offset r15, -1 * 4
nop
.balign 16
sigreturn_codes:
/* [EO]ABI sigreturn */
slot 0
raw_syscall __NR_sigreturn
.cfi_def_cfa_offset 160 + 64
/* [EO]ABI rt_sigreturn */
slot 1
raw_syscall __NR_rt_sigreturn
.cfi_endproc
/* FDPIC sigreturn */
.cfi_startproc
cfi_fdpic_pc SIGFRAME_RC3_OFFSET
cfi_fdpic_r9 SIGFRAME_RC3_OFFSET
slot 2
fdpic_thunk SIGFRAME_RC3_OFFSET
.cfi_endproc
/* FDPIC rt_sigreturn */
.cfi_startproc
cfi_fdpic_pc RT_SIGFRAME_RC3_OFFSET
cfi_fdpic_r9 RT_SIGFRAME_RC3_OFFSET
slot 3
fdpic_thunk RT_SIGFRAME_RC3_OFFSET
.cfi_endproc
.balign 16
endf sigreturn_codes

67
linux-user/arm/vdso.ld Normal file
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@ -0,0 +1,67 @@
/*
* Linker script for linux arm replacement vdso.
*
* Copyright 2023 Linaro, Ltd.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
VERSION {
LINUX_2.6 {
global:
__vdso_clock_gettime;
__vdso_gettimeofday;
__vdso_clock_getres;
__vdso_clock_gettime64;
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
/*
* 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
}

3
linux-user/elfload.c
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@ -944,13 +944,14 @@ const char *elf_hwcap2_str(uint32_t bit)
#undef GET_FEATURE_ID
#endif /* not TARGET_AARCH64 */
#if TARGET_BIG_ENDIAN
# define VDSO_HEADER "vdso-be.c.inc"
#else
# define VDSO_HEADER "vdso-le.c.inc"
#endif
#endif /* not TARGET_AARCH64 */
#endif /* TARGET_ARM */
#ifdef TARGET_SPARC