[PATCH V4 12/17] riscv: compat: vdso: Add rv32 VDSO base code implementation
From: guoren@kernel.org
Date: 2022-01-29 12:20:29
Also in:
linux-arch, linux-arm-kernel, linux-mips, linux-riscv, linux-s390, linuxppc-dev, lkml
Subsystem:
risc-v architecture, the rest · Maintainers:
Paul Walmsley, Palmer Dabbelt, Albert Ou, Linus Torvalds
From: Guo Ren <redacted>
There is no vgettimeofday supported in rv32 that makes simple to
generate rv32 vdso code which only needs riscv64 compiler. Other
architectures need change compiler or -m (machine parameter) to
support vdso32 compiling. If rv32 support vgettimeofday (which
cause C compile) in future, we would add CROSS_COMPILE to support
that makes more requirement on compiler enviornment.
linux-rv64/arch/riscv/kernel/compat_vdso/compat_vdso.so.dbg:
file format elf64-littleriscv
Disassembly of section .text:
0000000000000800 <__vdso_rt_sigreturn>:
800: 08b00893 li a7,139
804: 00000073 ecall
808: 0000 unimp
...
000000000000080c <__vdso_getcpu>:
80c: 0a800893 li a7,168
810: 00000073 ecall
814: 8082 ret
...
0000000000000818 <__vdso_flush_icache>:
818: 10300893 li a7,259
81c: 00000073 ecall
820: 8082 ret
linux-rv32/arch/riscv/kernel/vdso/vdso.so.dbg:
file format elf32-littleriscv
Disassembly of section .text:
00000800 <__vdso_rt_sigreturn>:
800: 08b00893 li a7,139
804: 00000073 ecall
808: 0000 unimp
...
0000080c <__vdso_getcpu>:
80c: 0a800893 li a7,168
810: 00000073 ecall
814: 8082 ret
...
00000818 <__vdso_flush_icache>:
818: 10300893 li a7,259
81c: 00000073 ecall
820: 8082 ret
Finally, reuse all *.S from vdso in compat_vdso that makes
implementation clear and readable.
Signed-off-by: Guo Ren <redacted>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
---
arch/riscv/Makefile | 5 ++
arch/riscv/include/asm/vdso.h | 9 +++
arch/riscv/kernel/Makefile | 1 +
arch/riscv/kernel/compat_vdso/.gitignore | 2 +
arch/riscv/kernel/compat_vdso/Makefile | 68 +++++++++++++++++++
arch/riscv/kernel/compat_vdso/compat_vdso.S | 8 +++
.../kernel/compat_vdso/compat_vdso.lds.S | 3 +
arch/riscv/kernel/compat_vdso/flush_icache.S | 3 +
.../compat_vdso/gen_compat_vdso_offsets.sh | 5 ++
arch/riscv/kernel/compat_vdso/getcpu.S | 3 +
arch/riscv/kernel/compat_vdso/note.S | 3 +
arch/riscv/kernel/compat_vdso/rt_sigreturn.S | 3 +
arch/riscv/kernel/vdso/vdso.S | 6 +-
13 files changed, 118 insertions(+), 1 deletion(-)
create mode 100644 arch/riscv/kernel/compat_vdso/.gitignore
create mode 100644 arch/riscv/kernel/compat_vdso/Makefile
create mode 100644 arch/riscv/kernel/compat_vdso/compat_vdso.S
create mode 100644 arch/riscv/kernel/compat_vdso/compat_vdso.lds.S
create mode 100644 arch/riscv/kernel/compat_vdso/flush_icache.S
create mode 100755 arch/riscv/kernel/compat_vdso/gen_compat_vdso_offsets.sh
create mode 100644 arch/riscv/kernel/compat_vdso/getcpu.S
create mode 100644 arch/riscv/kernel/compat_vdso/note.S
create mode 100644 arch/riscv/kernel/compat_vdso/rt_sigreturn.S
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index a02e588c4947..f73d50552e09 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile@@ -106,12 +106,17 @@ libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a PHONY += vdso_install vdso_install: $(Q)$(MAKE) $(build)=arch/riscv/kernel/vdso $@ + $(if $(CONFIG_COMPAT),$(Q)$(MAKE) \ + $(build)=arch/riscv/kernel/compat_vdso $@) ifeq ($(KBUILD_EXTMOD),) ifeq ($(CONFIG_MMU),y) prepare: vdso_prepare vdso_prepare: prepare0 $(Q)$(MAKE) $(build)=arch/riscv/kernel/vdso include/generated/vdso-offsets.h + $(if $(CONFIG_COMPAT),$(Q)$(MAKE) \ + $(build)=arch/riscv/kernel/compat_vdso include/generated/compat_vdso-offsets.h) + endif endif
diff --git a/arch/riscv/include/asm/vdso.h b/arch/riscv/include/asm/vdso.h
index bc6f75f3a199..af981426fe0f 100644
--- a/arch/riscv/include/asm/vdso.h
+++ b/arch/riscv/include/asm/vdso.h@@ -21,6 +21,15 @@ #define VDSO_SYMBOL(base, name) \ (void __user *)((unsigned long)(base) + __vdso_##name##_offset) + +#ifdef CONFIG_COMPAT +#include <generated/compat_vdso-offsets.h> + +#define COMPAT_VDSO_SYMBOL(base, name) \ + (void __user *)((unsigned long)(base) + compat__vdso_##name##_offset) + +#endif /* CONFIG_COMPAT */ + #endif /* !__ASSEMBLY__ */ #endif /* CONFIG_MMU */
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index 954dc7043ad2..88e79f481c21 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile@@ -67,3 +67,4 @@ obj-$(CONFIG_JUMP_LABEL) += jump_label.o obj-$(CONFIG_EFI) += efi.o obj-$(CONFIG_COMPAT) += compat_syscall_table.o +obj-$(CONFIG_COMPAT) += compat_vdso/
diff --git a/arch/riscv/kernel/compat_vdso/.gitignore b/arch/riscv/kernel/compat_vdso/.gitignore
new file mode 100644
index 000000000000..19d83d846c1e
--- /dev/null
+++ b/arch/riscv/kernel/compat_vdso/.gitignore@@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +compat_vdso.lds
diff --git a/arch/riscv/kernel/compat_vdso/Makefile b/arch/riscv/kernel/compat_vdso/Makefile
new file mode 100644
index 000000000000..7bbbbf94307f
--- /dev/null
+++ b/arch/riscv/kernel/compat_vdso/Makefile@@ -0,0 +1,68 @@ +# SPDX-License-Identifier: GPL-2.0-only + +# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before +# the inclusion of generic Makefile. +ARCH_REL_TYPE_ABS := R_RISCV_32|R_RISCV_64|R_RISCV_JUMP_SLOT +include $(srctree)/lib/vdso/Makefile +# Symbols present in the compat_vdso +compat_vdso-syms = rt_sigreturn +compat_vdso-syms += getcpu +compat_vdso-syms += flush_icache + +# Files to link into the compat_vdso +obj-compat_vdso = $(patsubst %, %.o, $(compat_vdso-syms)) note.o + +ccflags-y := -fno-stack-protector + +# Build rules +targets := $(obj-compat_vdso) compat_vdso.so compat_vdso.so.dbg compat_vdso.lds +obj-compat_vdso := $(addprefix $(obj)/, $(obj-compat_vdso)) + +obj-y += compat_vdso.o +CPPFLAGS_compat_vdso.lds += -P -C -U$(ARCH) + +# Disable profiling and instrumentation for VDSO code +GCOV_PROFILE := n +KCOV_INSTRUMENT := n +KASAN_SANITIZE := n +UBSAN_SANITIZE := n + +# Force dependency +$(obj)/compat_vdso.o: $(obj)/compat_vdso.so + +# link rule for the .so file, .lds has to be first +$(obj)/compat_vdso.so.dbg: $(obj)/compat_vdso.lds $(obj-compat_vdso) FORCE + $(call if_changed,compat_vdsold) +LDFLAGS_compat_vdso.so.dbg = -shared -S -soname=linux-compat_vdso.so.1 \ + --build-id=sha1 --hash-style=both --eh-frame-hdr + +# strip rule for the .so file +$(obj)/%.so: OBJCOPYFLAGS := -S +$(obj)/%.so: $(obj)/%.so.dbg FORCE + $(call if_changed,objcopy) + +# Generate VDSO offsets using helper script +gen-compat_vdsosym := $(srctree)/$(src)/gen_compat_vdso_offsets.sh +quiet_cmd_compat_vdsosym = VDSOSYM $@ + cmd_compat_vdsosym = $(NM) $< | $(gen-compat_vdsosym) | LC_ALL=C sort > $@ + +include/generated/compat_vdso-offsets.h: $(obj)/compat_vdso.so.dbg FORCE + $(call if_changed,compat_vdsosym) + +# actual build commands +# The DSO images are built using a special linker script +# Make sure only to export the intended __compat_vdso_xxx symbol offsets. +quiet_cmd_compat_vdsold = VDSOLD $@ + cmd_compat_vdsold = $(LD) $(ld_flags) -T $(filter-out FORCE,$^) -o $@.tmp && \ + $(OBJCOPY) $(patsubst %, -G __compat_vdso_%, $(compat_vdso-syms)) $@.tmp $@ && \ + rm $@.tmp + +# install commands for the unstripped file +quiet_cmd_compat_vdso_install = INSTALL $@ + cmd_compat_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/compat_vdso/$@ + +compat_vdso.so: $(obj)/compat_vdso.so.dbg + @mkdir -p $(MODLIB)/compat_vdso + $(call cmd,compat_vdso_install) + +compat_vdso_install: compat_vdso.so
diff --git a/arch/riscv/kernel/compat_vdso/compat_vdso.S b/arch/riscv/kernel/compat_vdso/compat_vdso.S
new file mode 100644
index 000000000000..fea4a8b0c45d
--- /dev/null
+++ b/arch/riscv/kernel/compat_vdso/compat_vdso.S@@ -0,0 +1,8 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#define vdso_start compat_vdso_start +#define vdso_end compat_vdso_end + +#define __VDSO_PATH "arch/riscv/kernel/compat_vdso/compat_vdso.so" + +#include <../vdso/vdso.S>
diff --git a/arch/riscv/kernel/compat_vdso/compat_vdso.lds.S b/arch/riscv/kernel/compat_vdso/compat_vdso.lds.S
new file mode 100644
index 000000000000..02a9ec5dc7f6
--- /dev/null
+++ b/arch/riscv/kernel/compat_vdso/compat_vdso.lds.S@@ -0,0 +1,3 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#include <../vdso/vdso.lds.S>
diff --git a/arch/riscv/kernel/compat_vdso/flush_icache.S b/arch/riscv/kernel/compat_vdso/flush_icache.S
new file mode 100644
index 000000000000..88e21a84a974
--- /dev/null
+++ b/arch/riscv/kernel/compat_vdso/flush_icache.S@@ -0,0 +1,3 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#include <../vdso/flush_icache.S>
diff --git a/arch/riscv/kernel/compat_vdso/gen_compat_vdso_offsets.sh b/arch/riscv/kernel/compat_vdso/gen_compat_vdso_offsets.sh
new file mode 100755
index 000000000000..8ac070c783b3
--- /dev/null
+++ b/arch/riscv/kernel/compat_vdso/gen_compat_vdso_offsets.sh@@ -0,0 +1,5 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 + +LC_ALL=C +sed -n -e 's/^[0]\+\(0[0-9a-fA-F]*\) . \(__vdso_[a-zA-Z0-9_]*\)$/\#define compat\2_offset\t0x\1/p'
diff --git a/arch/riscv/kernel/compat_vdso/getcpu.S b/arch/riscv/kernel/compat_vdso/getcpu.S
new file mode 100644
index 000000000000..946449a15a94
--- /dev/null
+++ b/arch/riscv/kernel/compat_vdso/getcpu.S@@ -0,0 +1,3 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#include <../vdso/getcpu.S>
diff --git a/arch/riscv/kernel/compat_vdso/note.S b/arch/riscv/kernel/compat_vdso/note.S
new file mode 100644
index 000000000000..67c50898b8e5
--- /dev/null
+++ b/arch/riscv/kernel/compat_vdso/note.S@@ -0,0 +1,3 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#include <../vdso/note.S>
diff --git a/arch/riscv/kernel/compat_vdso/rt_sigreturn.S b/arch/riscv/kernel/compat_vdso/rt_sigreturn.S
new file mode 100644
index 000000000000..f4c98f18c053
--- /dev/null
+++ b/arch/riscv/kernel/compat_vdso/rt_sigreturn.S@@ -0,0 +1,3 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#include <../vdso/rt_sigreturn.S>
diff --git a/arch/riscv/kernel/vdso/vdso.S b/arch/riscv/kernel/vdso/vdso.S
index df222245be05..83f1c899e8d8 100644
--- a/arch/riscv/kernel/vdso/vdso.S
+++ b/arch/riscv/kernel/vdso/vdso.S@@ -7,12 +7,16 @@ #include <linux/linkage.h> #include <asm/page.h> +#ifndef __VDSO_PATH +#define __VDSO_PATH "arch/riscv/kernel/vdso/vdso.so" +#endif + __PAGE_ALIGNED_DATA .globl vdso_start, vdso_end .balign PAGE_SIZE vdso_start: - .incbin "arch/riscv/kernel/vdso/vdso.so" + .incbin __VDSO_PATH .balign PAGE_SIZE vdso_end:
--
2.25.1