diff options
| -rwxr-xr-x | arch/powerpc/tools/relocs_check.sh | 18 | ||||
| -rw-r--r-- | arch/riscv/Kconfig | 14 | ||||
| -rw-r--r-- | arch/riscv/Makefile | 7 | ||||
| -rw-r--r-- | arch/riscv/Makefile.postlink | 49 | ||||
| -rw-r--r-- | arch/riscv/boot/Makefile | 7 | ||||
| -rw-r--r-- | arch/riscv/include/asm/set_memory.h | 3 | ||||
| -rw-r--r-- | arch/riscv/include/asm/topology.h | 5 | ||||
| -rw-r--r-- | arch/riscv/kernel/efi-header.S | 19 | ||||
| -rw-r--r-- | arch/riscv/kernel/vmlinux.lds.S | 26 | ||||
| -rw-r--r-- | arch/riscv/mm/Makefile | 4 | ||||
| -rw-r--r-- | arch/riscv/mm/init.c | 54 | ||||
| -rwxr-xr-x | arch/riscv/tools/relocs_check.sh | 26 | ||||
| -rwxr-xr-x | scripts/relocs_check.sh | 20 |
13 files changed, 221 insertions, 31 deletions
diff --git a/arch/powerpc/tools/relocs_check.sh b/arch/powerpc/tools/relocs_check.sh index 63792af00417..6b350e75014c 100755 --- a/arch/powerpc/tools/relocs_check.sh +++ b/arch/powerpc/tools/relocs_check.sh @@ -15,21 +15,8 @@ if [ $# -lt 3 ]; then exit 1 fi -# Have Kbuild supply the path to objdump and nm so we handle cross compilation. -objdump="$1" -nm="$2" -vmlinux="$3" - -# Remove from the bad relocations those that match an undefined weak symbol -# which will result in an absolute relocation to 0. -# Weak unresolved symbols are of that form in nm output: -# " w _binary__btf_vmlinux_bin_end" -undef_weak_symbols=$($nm "$vmlinux" | awk '$1 ~ /w/ { print $2 }') - bad_relocs=$( -$objdump -R "$vmlinux" | - # Only look at relocation lines. - grep -E '\<R_' | +${srctree}/scripts/relocs_check.sh "$@" | # These relocations are okay # On PPC64: # R_PPC64_RELATIVE, R_PPC64_NONE @@ -44,8 +31,7 @@ R_PPC_ADDR16_LO R_PPC_ADDR16_HI R_PPC_ADDR16_HA R_PPC_RELATIVE -R_PPC_NONE' | - ([ "$undef_weak_symbols" ] && grep -F -w -v "$undef_weak_symbols" || cat) +R_PPC_NONE' ) if [ -z "$bad_relocs" ]; then diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 716e9480495d..c58d74235363 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -603,6 +603,20 @@ config COMPAT If you want to execute 32-bit userspace applications, say Y. +config RELOCATABLE + bool "Build a relocatable kernel" + depends on MMU && 64BIT && !XIP_KERNEL + help + This builds a kernel as a Position Independent Executable (PIE), + which retains all relocation metadata required to relocate the + kernel binary at runtime to a different virtual address than the + address it was linked at. + Since RISCV uses the RELA relocation format, this requires a + relocation pass at runtime even if the kernel is loaded at the + same address it was linked at. + + If unsure, say N. + endmenu # "Kernel features" menu "Boot options" diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile index 1b276f62f22b..e859e1721a8f 100644 --- a/arch/riscv/Makefile +++ b/arch/riscv/Makefile @@ -7,9 +7,12 @@ # OBJCOPYFLAGS := -O binary -LDFLAGS_vmlinux := +ifeq ($(CONFIG_RELOCATABLE),y) + LDFLAGS_vmlinux += -shared -Bsymbolic -z notext -z norelro --emit-relocs + KBUILD_CFLAGS += -fPIE +endif ifeq ($(CONFIG_DYNAMIC_FTRACE),y) - LDFLAGS_vmlinux := --no-relax + LDFLAGS_vmlinux += --no-relax KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY ifeq ($(CONFIG_RISCV_ISA_C),y) CC_FLAGS_FTRACE := -fpatchable-function-entry=4 diff --git a/arch/riscv/Makefile.postlink b/arch/riscv/Makefile.postlink new file mode 100644 index 000000000000..a46fc578b30b --- /dev/null +++ b/arch/riscv/Makefile.postlink @@ -0,0 +1,49 @@ +# SPDX-License-Identifier: GPL-2.0 +# =========================================================================== +# Post-link riscv pass +# =========================================================================== +# +# Check that vmlinux relocations look sane + +PHONY := __archpost +__archpost: + +-include include/config/auto.conf +include $(srctree)/scripts/Kbuild.include + +quiet_cmd_relocs_check = CHKREL $@ +cmd_relocs_check = \ + $(CONFIG_SHELL) $(srctree)/arch/riscv/tools/relocs_check.sh "$(OBJDUMP)" "$(NM)" "$@" + +ifdef CONFIG_RELOCATABLE +quiet_cmd_cp_vmlinux_relocs = CPREL vmlinux.relocs +cmd_cp_vmlinux_relocs = cp vmlinux vmlinux.relocs + +quiet_cmd_relocs_strip = STRIPREL $@ +cmd_relocs_strip = $(OBJCOPY) --remove-section='.rel.*' \ + --remove-section='.rel__*' \ + --remove-section='.rela.*' \ + --remove-section='.rela__*' $@ +endif + +# `@true` prevents complaint when there is nothing to be done + +vmlinux: FORCE + @true +ifdef CONFIG_RELOCATABLE + $(call if_changed,relocs_check) + $(call if_changed,cp_vmlinux_relocs) + $(call if_changed,relocs_strip) +endif + +%.ko: FORCE + @true + +clean: + @true + +PHONY += FORCE clean + +FORCE: + +.PHONY: $(PHONY) diff --git a/arch/riscv/boot/Makefile b/arch/riscv/boot/Makefile index c72de7232abb..22b13947bd13 100644 --- a/arch/riscv/boot/Makefile +++ b/arch/riscv/boot/Makefile @@ -33,7 +33,14 @@ $(obj)/xipImage: vmlinux FORCE endif +ifdef CONFIG_RELOCATABLE +vmlinux.relocs: vmlinux + @ (! [ -f vmlinux.relocs ] && echo "vmlinux.relocs can't be found, please remove vmlinux and try again") || true + +$(obj)/Image: vmlinux.relocs FORCE +else $(obj)/Image: vmlinux FORCE +endif $(call if_changed,objcopy) $(obj)/Image.gz: $(obj)/Image FORCE diff --git a/arch/riscv/include/asm/set_memory.h b/arch/riscv/include/asm/set_memory.h index a2c14d4b3993..ec11001c3fe0 100644 --- a/arch/riscv/include/asm/set_memory.h +++ b/arch/riscv/include/asm/set_memory.h @@ -56,4 +56,7 @@ bool kernel_page_present(struct page *page); #define SECTION_ALIGN L1_CACHE_BYTES #endif /* CONFIG_STRICT_KERNEL_RWX */ +#define PECOFF_SECTION_ALIGNMENT 0x1000 +#define PECOFF_FILE_ALIGNMENT 0x200 + #endif /* _ASM_RISCV_SET_MEMORY_H */ diff --git a/arch/riscv/include/asm/topology.h b/arch/riscv/include/asm/topology.h index 727e8d163a3b..e316ab3b77f3 100644 --- a/arch/riscv/include/asm/topology.h +++ b/arch/riscv/include/asm/topology.h @@ -5,8 +5,8 @@ #include <linux/arch_topology.h> /* Replace task scheduler's default frequency-invariant accounting */ -#define arch_scale_freq_tick topology_scale_freq_tick -#define arch_set_freq_scale topology_set_freq_scale +#define arch_scale_freq_tick topology_scale_freq_tick +#define arch_set_freq_scale topology_set_freq_scale #define arch_scale_freq_capacity topology_get_freq_scale #define arch_scale_freq_invariant topology_scale_freq_invariant @@ -17,4 +17,5 @@ #define arch_update_cpu_topology topology_update_cpu_topology #include <asm-generic/topology.h> + #endif /* _ASM_RISCV_TOPOLOGY_H */ diff --git a/arch/riscv/kernel/efi-header.S b/arch/riscv/kernel/efi-header.S index 8e733aa48ba6..515b2dfbca75 100644 --- a/arch/riscv/kernel/efi-header.S +++ b/arch/riscv/kernel/efi-header.S @@ -6,6 +6,7 @@ #include <linux/pe.h> #include <linux/sizes.h> +#include <asm/set_memory.h> .macro __EFI_PE_HEADER .long PE_MAGIC @@ -33,7 +34,11 @@ optional_header: .byte 0x02 // MajorLinkerVersion .byte 0x14 // MinorLinkerVersion .long __pecoff_text_end - efi_header_end // SizeOfCode - .long __pecoff_data_virt_size // SizeOfInitializedData +#ifdef __clang__ + .long __pecoff_data_virt_size // SizeOfInitializedData +#else + .long __pecoff_data_virt_end - __pecoff_text_end // SizeOfInitializedData +#endif .long 0 // SizeOfUninitializedData .long __efistub_efi_pe_entry - _start // AddressOfEntryPoint .long efi_header_end - _start // BaseOfCode @@ -91,9 +96,17 @@ section_table: IMAGE_SCN_MEM_EXECUTE // Characteristics .ascii ".data\0\0\0" - .long __pecoff_data_virt_size // VirtualSize +#ifdef __clang__ + .long __pecoff_data_virt_size // VirtualSize +#else + .long __pecoff_data_virt_end - __pecoff_text_end // VirtualSize +#endif .long __pecoff_text_end - _start // VirtualAddress - .long __pecoff_data_raw_size // SizeOfRawData +#ifdef __clang__ + .long __pecoff_data_raw_size // SizeOfRawData +#else + .long __pecoff_data_raw_end - __pecoff_text_end // SizeOfRawData +#endif .long __pecoff_text_end - _start // PointerToRawData .long 0 // PointerToRelocations diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S index 53a8ad65b255..615ff5842690 100644 --- a/arch/riscv/kernel/vmlinux.lds.S +++ b/arch/riscv/kernel/vmlinux.lds.S @@ -27,9 +27,6 @@ ENTRY(_start) jiffies = jiffies_64; -PECOFF_SECTION_ALIGNMENT = 0x1000; -PECOFF_FILE_ALIGNMENT = 0x200; - SECTIONS { /* Beginning of code and text segment */ @@ -99,10 +96,6 @@ SECTIONS *(.rel.dyn*) } - .rela.dyn : { - *(.rela*) - } - __init_data_end = .; . = ALIGN(8); @@ -129,9 +122,27 @@ SECTIONS *(.sdata*) } + .rela.dyn : ALIGN(8) { + __rela_dyn_start = .; + *(.rela .rela*) + __rela_dyn_end = .; + } + +#ifdef CONFIG_RELOCATABLE + .data.rel : { *(.data.rel*) } + .got : { *(.got*) } + .plt : { *(.plt) } + .dynamic : { *(.dynamic) } + .dynsym : { *(.dynsym) } + .dynstr : { *(.dynstr) } + .hash : { *(.hash) } + .gnu.hash : { *(.gnu.hash) } +#endif + #ifdef CONFIG_EFI .pecoff_edata_padding : { BYTE(0); . = ALIGN(PECOFF_FILE_ALIGNMENT); } __pecoff_data_raw_size = ABSOLUTE(. - __pecoff_text_end); + __pecoff_data_raw_end = ABSOLUTE(.); #endif /* End of data section */ @@ -142,6 +153,7 @@ SECTIONS #ifdef CONFIG_EFI . = ALIGN(PECOFF_SECTION_ALIGNMENT); __pecoff_data_virt_size = ABSOLUTE(. - __pecoff_text_end); + __pecoff_data_virt_end = ABSOLUTE(.); #endif _end = .; diff --git a/arch/riscv/mm/Makefile b/arch/riscv/mm/Makefile index 2ac177c05352..b85e9e82f082 100644 --- a/arch/riscv/mm/Makefile +++ b/arch/riscv/mm/Makefile @@ -1,6 +1,10 @@ # SPDX-License-Identifier: GPL-2.0-only CFLAGS_init.o := -mcmodel=medany +ifdef CONFIG_RELOCATABLE +CFLAGS_init.o += -fno-pie +endif + ifdef CONFIG_FTRACE CFLAGS_REMOVE_init.o = $(CC_FLAGS_FTRACE) CFLAGS_REMOVE_cacheflush.o = $(CC_FLAGS_FTRACE) diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index f803671d18b2..bce899b180cd 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -20,6 +20,9 @@ #include <linux/dma-map-ops.h> #include <linux/crash_dump.h> #include <linux/hugetlb.h> +#ifdef CONFIG_RELOCATABLE +#include <linux/elf.h> +#endif #include <asm/fixmap.h> #include <asm/tlbflush.h> @@ -146,7 +149,7 @@ static void __init print_vm_layout(void) print_ml("kasan", KASAN_SHADOW_START, KASAN_SHADOW_END); #endif - print_ml("kernel", (unsigned long)KERNEL_LINK_ADDR, + print_ml("kernel", (unsigned long)kernel_map.virt_addr, (unsigned long)ADDRESS_SPACE_END); } } @@ -831,6 +834,44 @@ retry: #error "setup_vm() is called from head.S before relocate so it should not use absolute addressing." #endif +#ifdef CONFIG_RELOCATABLE +extern unsigned long __rela_dyn_start, __rela_dyn_end; + +static void __init relocate_kernel(void) +{ + Elf64_Rela *rela = (Elf64_Rela *)&__rela_dyn_start; + /* + * This holds the offset between the linked virtual address and the + * relocated virtual address. + */ + uintptr_t reloc_offset = kernel_map.virt_addr - KERNEL_LINK_ADDR; + /* + * This holds the offset between kernel linked virtual address and + * physical address. + */ + uintptr_t va_kernel_link_pa_offset = KERNEL_LINK_ADDR - kernel_map.phys_addr; + + for ( ; rela < (Elf64_Rela *)&__rela_dyn_end; rela++) { + Elf64_Addr addr = (rela->r_offset - va_kernel_link_pa_offset); + Elf64_Addr relocated_addr = rela->r_addend; + + if (rela->r_info != R_RISCV_RELATIVE) + continue; + + /* + * Make sure to not relocate vdso symbols like rt_sigreturn + * which are linked from the address 0 in vmlinux since + * vdso symbol addresses are actually used as an offset from + * mm->context.vdso in VDSO_OFFSET macro. + */ + if (relocated_addr >= KERNEL_LINK_ADDR) + relocated_addr += reloc_offset; + + *(Elf64_Addr *)addr = relocated_addr; + } +} +#endif /* CONFIG_RELOCATABLE */ + #ifdef CONFIG_XIP_KERNEL static void __init create_kernel_page_table(pgd_t *pgdir, __always_unused bool early) @@ -1029,6 +1070,17 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) BUG_ON((kernel_map.virt_addr + kernel_map.size) > ADDRESS_SPACE_END - SZ_4K); #endif +#ifdef CONFIG_RELOCATABLE + /* + * Early page table uses only one PUD, which makes it possible + * to map PUD_SIZE aligned on PUD_SIZE: if the relocation offset + * makes the kernel cross over a PUD_SIZE boundary, raise a bug + * since a part of the kernel would not get mapped. + */ + BUG_ON(PUD_SIZE - (kernel_map.virt_addr & (PUD_SIZE - 1)) < kernel_map.size); + relocate_kernel(); +#endif + apply_early_boot_alternatives(); pt_ops_set_early(); diff --git a/arch/riscv/tools/relocs_check.sh b/arch/riscv/tools/relocs_check.sh new file mode 100755 index 000000000000..baeb2e7b2290 --- /dev/null +++ b/arch/riscv/tools/relocs_check.sh @@ -0,0 +1,26 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-or-later +# Based on powerpc relocs_check.sh + +# This script checks the relocations of a vmlinux for "suspicious" +# relocations. + +if [ $# -lt 3 ]; then + echo "$0 [path to objdump] [path to nm] [path to vmlinux]" 1>&2 + exit 1 +fi + +bad_relocs=$( +${srctree}/scripts/relocs_check.sh "$@" | + # These relocations are okay + # R_RISCV_RELATIVE + grep -F -w -v 'R_RISCV_RELATIVE' +) + +if [ -z "$bad_relocs" ]; then + exit 0 +fi + +num_bad=$(echo "$bad_relocs" | wc -l) +echo "WARNING: $num_bad bad relocations" +echo "$bad_relocs" diff --git a/scripts/relocs_check.sh b/scripts/relocs_check.sh new file mode 100755 index 000000000000..137c660499f3 --- /dev/null +++ b/scripts/relocs_check.sh @@ -0,0 +1,20 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-or-later + +# Get a list of all the relocations, remove from it the relocations +# that are known to be legitimate and return this list to arch specific +# script that will look for suspicious relocations. + +objdump="$1" +nm="$2" +vmlinux="$3" + +# Remove from the possible bad relocations those that match an undefined +# weak symbol which will result in an absolute relocation to 0. +# Weak unresolved symbols are of that form in nm output: +# " w _binary__btf_vmlinux_bin_end" +undef_weak_symbols=$($nm "$vmlinux" | awk '$1 ~ /w/ { print $2 }') + +$objdump -R "$vmlinux" | + grep -E '\<R_' | + ([ "$undef_weak_symbols" ] && grep -F -w -v "$undef_weak_symbols" || cat) |