From: "Philippe Mathieu-Daudé" <philmd@linaro.org>
To: Richard Henderson <richard.henderson@linaro.org>, qemu-devel@nongnu.org
Cc: alex.bennee@linaro.org, laurent@vivier.eu,
Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH v6 09/19] linux-user/i386: Add vdso
Date: Thu, 5 Oct 2023 18:42:20 +0200 [thread overview]
Message-ID: <cc32e744-85a2-65c7-f179-92bb37a754f6@linaro.org> (raw)
In-Reply-To: <20230930021529.987950-10-richard.henderson@linaro.org>
On 30/9/23 04:15, Richard Henderson wrote:
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1267
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
> linux-user/i386/vdso-asmoffset.h | 6 ++
> linux-user/elfload.c | 19 +++-
> linux-user/i386/signal.c | 11 +++
> linux-user/i386/Makefile.vdso | 11 +++
> linux-user/i386/meson.build | 7 ++
> linux-user/i386/vdso.S | 143 +++++++++++++++++++++++++++++++
> linux-user/i386/vdso.ld | 76 ++++++++++++++++
> linux-user/i386/vdso.so | Bin 0 -> 2672 bytes
> 8 files changed, 271 insertions(+), 2 deletions(-)
> create mode 100644 linux-user/i386/vdso-asmoffset.h
> create mode 100644 linux-user/i386/Makefile.vdso
> create mode 100644 linux-user/i386/vdso.S
> create mode 100644 linux-user/i386/vdso.ld
> create mode 100755 linux-user/i386/vdso.so
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> diff --git a/linux-user/i386/vdso-asmoffset.h b/linux-user/i386/vdso-asmoffset.h
> new file mode 100644
> index 0000000000..4e5ee0dd49
> --- /dev/null
> +++ b/linux-user/i386/vdso-asmoffset.h
> @@ -0,0 +1,6 @@
> +/*
> + * offsetof(struct sigframe, sc.eip)
> + * offsetof(struct rt_sigframe, uc.tuc_mcontext.eip)
> + */
> +#define SIGFRAME_SIGCONTEXT_eip 64
> +#define RT_SIGFRAME_SIGCONTEXT_eip 220
> diff --git a/linux-user/elfload.c b/linux-user/elfload.c
> index 9c97d14b7e..314ae7cacf 100644
> --- a/linux-user/elfload.c
> +++ b/linux-user/elfload.c
> @@ -305,12 +305,27 @@ static void elf_core_copy_regs(target_elf_gregset_t *regs, const CPUX86State *en
> (*regs)[15] = tswapreg(env->regs[R_ESP]);
> (*regs)[16] = tswapreg(env->segs[R_SS].selector & 0xffff);
> }
> -#endif
> +
> +/*
> + * i386 is the only target which supplies AT_SYSINFO for the vdso.
> + * All others only supply AT_SYSINFO_EHDR.
> + */
> +#define DLINFO_ARCH_ITEMS (vdso_info != NULL)
> +#define ARCH_DLINFO \
> + do { \
> + if (vdso_info) { \
> + NEW_AUX_ENT(AT_SYSINFO, vdso_info->entry); \
> + } \
> + } while (0)
> +
> +#define VDSO_HEADER "vdso.c.inc"
> +
> +#endif /* TARGET_X86_64 */
>
> #define USE_ELF_CORE_DUMP
> #define ELF_EXEC_PAGESIZE 4096
>
> -#endif
> +#endif /* TARGET_I386 */
>
> #ifdef TARGET_ARM
>
> diff --git a/linux-user/i386/signal.c b/linux-user/i386/signal.c
> index 60fa07d6f9..bc5d45302e 100644
> --- a/linux-user/i386/signal.c
> +++ b/linux-user/i386/signal.c
> @@ -214,6 +214,17 @@ struct rt_sigframe {
> };
> #define TARGET_RT_SIGFRAME_FXSAVE_OFFSET ( \
> offsetof(struct rt_sigframe, fpstate) + TARGET_FPSTATE_FXSAVE_OFFSET)
> +
> +/*
> + * Verify that vdso-asmoffset.h constants match.
> + */
> +#include "i386/vdso-asmoffset.h"
> +
> +QEMU_BUILD_BUG_ON(offsetof(struct sigframe, sc.eip)
> + != SIGFRAME_SIGCONTEXT_eip);
> +QEMU_BUILD_BUG_ON(offsetof(struct rt_sigframe, uc.tuc_mcontext.eip)
> + != RT_SIGFRAME_SIGCONTEXT_eip);
> +
> #else
>
> struct rt_sigframe {
> diff --git a/linux-user/i386/Makefile.vdso b/linux-user/i386/Makefile.vdso
> new file mode 100644
> index 0000000000..95bc616f6d
> --- /dev/null
> +++ b/linux-user/i386/Makefile.vdso
> @@ -0,0 +1,11 @@
> +include $(BUILD_DIR)/tests/tcg/i386-linux-user/config-target.mak
> +
> +SUBDIR = $(SRC_PATH)/linux-user/i386
> +VPATH += $(SUBDIR)
> +
> +all: $(SUBDIR)/vdso.so
> +
> +$(SUBDIR)/vdso.so: vdso.S vdso.ld vdso-asmoffset.h
> + $(CC) -o $@ -m32 -nostdlib -shared -Wl,-h,linux-gate.so.1 \
> + -Wl,--build-id=sha1 -Wl,--hash-style=both \
> + -Wl,-T,$(SUBDIR)/vdso.ld $<
> diff --git a/linux-user/i386/meson.build b/linux-user/i386/meson.build
> index ee523019a5..d42fc6cbc9 100644
> --- a/linux-user/i386/meson.build
> +++ b/linux-user/i386/meson.build
> @@ -3,3 +3,10 @@ syscall_nr_generators += {
> arguments: [ meson.current_source_dir() / 'syscallhdr.sh', '@INPUT@', '@OUTPUT@', '@EXTRA_ARGS@' ],
> output: '@BASENAME@_nr.h')
> }
> +
> +vdso_inc = gen_vdso.process('vdso.so', extra_args: [
> + '-s', '__kernel_sigreturn',
> + '-r', '__kernel_rt_sigreturn'
> + ])
> +
> +linux_user_ss.add(when: 'TARGET_I386', if_true: vdso_inc)
> diff --git a/linux-user/i386/vdso.S b/linux-user/i386/vdso.S
> new file mode 100644
> index 0000000000..e7a1f333a1
> --- /dev/null
> +++ b/linux-user/i386/vdso.S
> @@ -0,0 +1,143 @@
> +/*
> + * i386 linux replacement vdso.
> + *
> + * Copyright 2023 Linaro, Ltd.
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +
> +#include <asm/unistd.h>
> +#include "vdso-asmoffset.h"
> +
> +.macro endf name
> + .globl \name
> + .type \name, @function
> + .size \name, . - \name
> +.endm
> +
> +.macro vdso_syscall1 name, nr
> +\name:
> + .cfi_startproc
> + mov %ebx, %edx
> + .cfi_register %ebx, %edx
> + mov 4(%esp), %ebx
> + mov $\nr, %eax
> + int $0x80
> + mov %edx, %ebx
> + ret
> + .cfi_endproc
> +endf \name
> +.endm
> +
> +.macro vdso_syscall2 name, nr
> +\name:
> + .cfi_startproc
> + mov %ebx, %edx
> + .cfi_register %ebx, %edx
> + mov 4(%esp), %ebx
> + mov 8(%esp), %ecx
> + mov $\nr, %eax
> + int $0x80
> + mov %edx, %ebx
> + ret
> + .cfi_endproc
> +endf \name
> +.endm
> +
> +.macro vdso_syscall3 name, nr
> +\name:
> + .cfi_startproc
> + push %ebx
> + .cfi_adjust_cfa_offset 4
> + .cfi_rel_offset %ebx, 0
> + mov 8(%esp), %ebx
> + mov 12(%esp), %ecx
> + mov 16(%esp), %edx
> + mov $\nr, %eax
> + int $0x80
> + pop %ebx
> + .cfi_adjust_cfa_offset -4
> + .cfi_restore %ebx
> + ret
> + .cfi_endproc
> +endf \name
> +.endm
> +
> +__kernel_vsyscall:
> + .cfi_startproc
> + int $0x80
> + ret
> + .cfi_endproc
> +endf __kernel_vsyscall
> +
> +vdso_syscall2 __vdso_clock_gettime, __NR_clock_gettime
> +vdso_syscall2 __vdso_clock_gettime64, __NR_clock_gettime64
> +vdso_syscall2 __vdso_clock_getres, __NR_clock_getres
> +vdso_syscall2 __vdso_gettimeofday, __NR_gettimeofday
> +vdso_syscall1 __vdso_time, __NR_time
> +vdso_syscall3 __vdso_getcpu, __NR_gettimeofday
> +
> +/*
> + * Signal return handlers.
> + */
> +
> + .cfi_startproc simple
> + .cfi_signal_frame
> +
> +/*
> + * For convenience, put the cfa just above eip in sigcontext, and count
> + * offsets backward from there. Re-compute the cfa in the two contexts
> + * we have for signal unwinding. This is far simpler than the
> + * DW_CFA_expression form that the kernel uses, and is equally correct.
> + */
> +
> + .cfi_def_cfa %esp, SIGFRAME_SIGCONTEXT_eip + 4
> +
> + .cfi_offset %eip, -4
> + /* err, -8 */
> + /* trapno, -12 */
> + .cfi_offset %eax, -16
> + .cfi_offset %ecx, -20
> + .cfi_offset %edx, -24
> + .cfi_offset %ebx, -28
> + .cfi_offset %esp, -32
> + .cfi_offset %ebp, -36
> + .cfi_offset %esi, -40
> + .cfi_offset %edi, -44
> +
> +/*
> + * While this frame is marked as a signal frame, that only applies to how
> + * the return address is handled for the outer frame. The return address
> + * that arrived here, from the inner frame, is not marked as a signal frame
> + * and so the unwinder still tries to subtract 1 to examine the presumed
> + * call insn. Thus we must extend the unwind info to a nop before the start.
> + */
> + nop
> +
> +__kernel_sigreturn:
> + popl %eax /* pop sig */
> + .cfi_adjust_cfa_offset -4
> + movl $__NR_sigreturn, %eax
> + int $0x80
> +endf __kernel_sigreturn
> +
> + .cfi_def_cfa_offset RT_SIGFRAME_SIGCONTEXT_eip + 4
> + nop
> +
> +__kernel_rt_sigreturn:
> + movl $__NR_rt_sigreturn, %eax
> + int $0x80
> +endf __kernel_rt_sigreturn
> +
> + .cfi_endproc
> +
> +/*
> + * TODO: Add elf notes. E.g.
> + *
> + * #include <linux/elfnote.h>
> + * ELFNOTE_START(Linux, 0, "a")
> + * .long LINUX_VERSION_CODE
> + * ELFNOTE_END
> + *
> + * but what version number would we set for QEMU?
> + */
> diff --git a/linux-user/i386/vdso.ld b/linux-user/i386/vdso.ld
> new file mode 100644
> index 0000000000..326b7a8f98
> --- /dev/null
> +++ b/linux-user/i386/vdso.ld
> @@ -0,0 +1,76 @@
> +/*
> + * Linker script for linux i386 replacement vdso.
> + *
> + * Copyright 2023 Linaro, Ltd.
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +
> +ENTRY(__kernel_vsyscall)
> +
> +VERSION {
> + LINUX_2.6 {
> + global:
> + __vdso_clock_gettime;
> + __vdso_gettimeofday;
> + __vdso_time;
> + __vdso_clock_getres;
> + __vdso_clock_gettime64;
> + __vdso_getcpu;
> + };
> +
> + LINUX_2.5 {
> + global:
> + __kernel_vsyscall;
> + __kernel_sigreturn;
> + __kernel_rt_sigreturn;
> + 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 =0x90909090
> +}
> diff --git a/linux-user/i386/vdso.so b/linux-user/i386/vdso.so
> new file mode 100755
> index 0000000000000000000000000000000000000000..bdece5dfcf8da036d013262d4e37208350283cfa
> GIT binary patch
> literal 2672
> zcmbtWU1%It6u#5lG_z^4ZB?X_C>9o5sxCF8QBlyONt?nZ)?|y73e)ZGba%;SR(597
> zjTXE8QIiHtY6YPbDhO>6s(mPS(FX(Z2Q`g?1xp_^KInr_=|f8&)b;yj=5}w=eGok1
> z%XiMX=brmB_ny0ldSlx(O%qZAA|PnR8-(ZpuhYGj4)L&P5F5p65f&@qVw=PV(21ar
> zS~fT!zaSUUNMnr<D?qmul%W%{|IXi?lnz58hBiXBldmd>Kqu7p`(Ouv?E|~S#J4vR
> z?eBj&+ji~rg~eZ!zf~VSJr_pXM}D8DFrl0ORPzVHn5LKmbB!e|qzOC^tO77~@mIB)
> zzl6kpgPDI3e2U8d6uIY2bq_`x0-wZWxDMLSfe$J6M%crOeHivUY<@1rr@`l7bI!EC
> z1WQ>fZdBic@iW@_P1t@f_$4LZXEGSfcpH2f?e~Kj&v`Zj+$T!NBlkb|jQhnHeiL+a
> z&lJb<kCS@_*v@tHJTOn=lluBDy{$|iW0~jDvC(tlyVi??Q=2p0KUP})m@B{A^3Fp?
> z#y5Ta$e&ZC6Ayg2)jAG+!^M53FpOcdV3|2%)E={wiChkz(UhGxlDT|x*hrg>lO18$
> z-OkRAyW9oSmOj5{et#-4CVgruv?pIJqQxKI&ZY~dQ!H3DSHUrA-dxrymL5+h95ZU?
> zqfdy~j)7gfjrM5g9c>HN9>C7<kIZ}NS==-4@5JK#YMzfafM=QF?WZPg6+aHhHu){t
> z#@l_<Z)3bX7g}rJnLgP3J~0HQz%PJH;3Rk&d;okNJPDowp8;P3e*#_ve+BLUI4(td
> zZBS?jb*;5I7#xS6XOVMV0Ql`GjNJ_U;OnA06ySNFpY!>?j(;zF-_-GQuCsOgock95
> z$CvrnLFHO513c5BE36+~5f2BEAVM30`47nj^o(oe;NgZND~~oF)87oe)%5l%caD!C
> zZUR`#4&CABw}%(BE9KdV>yxiUf|Id`UI}64SIQGVslJnSd`)$H14yd$t+Ysc2<dgC
> zZ=Q@t)>OQ(J+srhD+k<&>B<F{@o$-65V!Wyt>HxRj<L>q5)uze70i3T0nE36-;4MD
> zX|P(C`eCbeVGnF6>~F$Q>&)x0)jBo>TdiYfVXJlMbJ%KKV=Y$enlO4^9_Z@du@yHB
> zwchCMGqw$O_4gWmJ%e{HQ)lfOF0TyrZnl4$<)z$G>%HU>FE1lXy;xFj>Xa70cGRgB
> zZe?<tMbsV}aT5E$PQl}h)U3Q?ifC%gN{nQau7X$*O<ToiCShkhk5lkGqh`U*=B*`$
> zkrGieW9%;^Moc4<LZq}r)G<pAcKN?aE5cZ-d1tTskoO0sTmQ-H0oHh)quV~pVEQOL
> zf~-B80KOf}$M=_*fzCLdUB>YqcLID@7{~XU=z-4s6vh$lz%9JdjN|)G?1a8N?pfc*
> zIKKY`&zcmDP2m_-KOf(Hg0)2EV}IgBfWHx_^Y;P~hc5SkbEE79n459x?;V(~$T$m@
> zjElobxDGGOT`N`AK*n(#-do~0bSZKjGMDr(AZ`H$D-74d^xS8@>$IiJAn|o+fMq_`
> OKQ-<Y4#gXF;{FA}h_Ctp
>
> literal 0
> HcmV?d00001
>
next prev parent reply other threads:[~2023-10-05 16:43 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-30 2:15 [PATCH v6 00/19] linux-user: Implement VDSOs Richard Henderson
2023-09-30 2:15 ` [PATCH v6 01/19] linux-user: Introduce imgsrc_read, imgsrc_read_alloc Richard Henderson
2023-09-30 2:15 ` [PATCH v6 02/19] linux-user: Tidy loader_exec Richard Henderson
2023-09-30 2:15 ` [PATCH v6 03/19] linux-user: Do not clobber bprm_buf swapping ehdr Richard Henderson
2023-09-30 2:15 ` [PATCH v6 04/19] linux-user: Use ImageSource in load_elf_image Richard Henderson
2023-10-02 13:22 ` Philippe Mathieu-Daudé
2023-09-30 2:15 ` [PATCH v6 05/19] linux-user: Use ImageSource in load_symbols Richard Henderson
2023-09-30 2:15 ` [PATCH v6 06/19] linux-user: Replace bprm->fd with bprm->src.fd Richard Henderson
2023-09-30 2:15 ` [PATCH v6 07/19] linux-user: Load vdso image if available Richard Henderson
2023-10-03 12:47 ` Philippe Mathieu-Daudé
2023-09-30 2:15 ` [PATCH v6 08/19] linux-user: Add gen-vdso tool Richard Henderson
2023-10-03 13:00 ` Philippe Mathieu-Daudé
2023-10-03 23:05 ` Richard Henderson
2023-10-05 16:25 ` Philippe Mathieu-Daudé
2023-09-30 2:15 ` [PATCH v6 09/19] linux-user/i386: Add vdso Richard Henderson
2023-10-05 16:42 ` Philippe Mathieu-Daudé [this message]
2023-09-30 2:15 ` [PATCH v6 10/19] linux-user/x86_64: " Richard Henderson
2023-10-05 16:44 ` Philippe Mathieu-Daudé
2023-09-30 2:15 ` [PATCH v6 11/19] linux-user/aarch64: " Richard Henderson
2023-10-05 16:47 ` Philippe Mathieu-Daudé
2023-09-30 2:15 ` [PATCH v6 12/19] linux-user/arm: " Richard Henderson
2023-09-30 2:15 ` [PATCH v6 13/19] linux-user/hppa: " Richard Henderson
2023-10-05 16:16 ` Philippe Mathieu-Daudé
2023-09-30 2:15 ` [PATCH v6 14/19] linux-user/riscv: " Richard Henderson
2023-10-05 16:24 ` Philippe Mathieu-Daudé
2023-09-30 2:15 ` [PATCH v6 15/19] linux-user/loongarch64: " Richard Henderson
2023-10-05 16:18 ` Philippe Mathieu-Daudé
2023-09-30 2:15 ` [PATCH v6 16/19] linux-user/ppc: " Richard Henderson
2023-10-05 16:35 ` Philippe Mathieu-Daudé
2023-09-30 2:15 ` [PATCH v6 17/19] linux-user/s390x: Rename __SIGNAL_FRAMESIZE to STACK_FRAME_OVERHEAD Richard Henderson
2023-09-30 2:15 ` [PATCH v6 18/19] linux-user/s390x: Add vdso Richard Henderson
2023-10-03 13:07 ` Philippe Mathieu-Daudé
2023-10-03 23:01 ` Richard Henderson
2023-10-05 16:14 ` Philippe Mathieu-Daudé
2023-10-06 7:30 ` Thomas Huth
2023-09-30 2:15 ` [PATCH v6 19/19] build: Add update-linux-vdso makefile rule Richard Henderson
2023-10-03 13:02 ` Philippe Mathieu-Daudé
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