From fb7183ef3c016d9067ff83f3ff2455be1818f902 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 31 Oct 2014 09:22:04 -0700 Subject: x86, boot: Document intermediates more clearly This adds a comment detailing the various intermediate files used to build the bootable decompression image for the x86 kernel. Signed-off-by: Kees Cook Reviewed-by: Josh Triplett Cc: Matt Fleming Cc: Ard Biesheuvel Cc: Junjie Mao Link: http://lkml.kernel.org/r/20141031162204.GA26268@www.outflux.net Signed-off-by: Thomas Gleixner --- arch/x86/boot/compressed/Makefile | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'arch/x86') diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 704f58aa79cd..8a3918180a9e 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -3,6 +3,18 @@ # # create a compressed vmlinux image from the original vmlinux # +# vmlinuz is: +# decompression code (*.o) +# asm globals (piggy.S), including: +# vmlinux.bin.(gz|bz2|lzma|...) +# +# vmlinux.bin is: +# vmlinux stripped of debugging and comments +# vmlinux.bin.all is: +# vmlinux.bin + vmlinux.relocs +# vmlinux.bin.(gz|bz2|lzma|...) is: +# (see scripts/Makefile.lib size_append) +# compressed vmlinux.bin.all + u32 size of vmlinux.bin.all targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \ vmlinux.bin.xz vmlinux.bin.lzo vmlinux.bin.lz4 -- cgit v1.2.2 From 2c773dd31fbacbbb6425f8a9d3f97e0010272368 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Tue, 4 Nov 2014 08:26:42 +0000 Subject: x86: Convert a few more per-CPU items to read-mostly ones Both this_cpu_off and cpu_info aren't getting modified post boot, yet are being accessed on enough code paths that grouping them with other frequently read items seems desirable. For cpu_info this at the same time implies removing the cache line alignment (which afaict became pointless when it got converted to per-CPU data years ago). Signed-off-by: Jan Beulich Link: http://lkml.kernel.org/r/54589BD20200007800044A84@mail.emea.novell.com Signed-off-by: Thomas Gleixner --- arch/x86/include/asm/percpu.h | 2 +- arch/x86/include/asm/processor.h | 4 ++-- arch/x86/kernel/setup_percpu.c | 2 +- arch/x86/kernel/smpboot.c | 2 +- 4 files changed, 5 insertions(+), 5 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h index fd472181a1d0..74da3178d776 100644 --- a/arch/x86/include/asm/percpu.h +++ b/arch/x86/include/asm/percpu.h @@ -522,7 +522,7 @@ static inline int x86_this_cpu_variable_test_bit(int nr, #include /* We can use this directly for local CPU (faster). */ -DECLARE_PER_CPU(unsigned long, this_cpu_off); +DECLARE_PER_CPU_READ_MOSTLY(unsigned long, this_cpu_off); #endif /* !__ASSEMBLY__ */ diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index eb71ec794732..3aeb31cc0511 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -127,7 +127,7 @@ struct cpuinfo_x86 { /* Index into per_cpu list: */ u16 cpu_index; u32 microcode; -} __attribute__((__aligned__(SMP_CACHE_BYTES))); +}; #define X86_VENDOR_INTEL 0 #define X86_VENDOR_CYRIX 1 @@ -151,7 +151,7 @@ extern __u32 cpu_caps_cleared[NCAPINTS]; extern __u32 cpu_caps_set[NCAPINTS]; #ifdef CONFIG_SMP -DECLARE_PER_CPU_SHARED_ALIGNED(struct cpuinfo_x86, cpu_info); +DECLARE_PER_CPU_READ_MOSTLY(struct cpuinfo_x86, cpu_info); #define cpu_data(cpu) per_cpu(cpu_info, cpu) #else #define cpu_info boot_cpu_data diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c index 5cdff0357746..e4fcb87ba7a6 100644 --- a/arch/x86/kernel/setup_percpu.c +++ b/arch/x86/kernel/setup_percpu.c @@ -30,7 +30,7 @@ EXPORT_PER_CPU_SYMBOL(cpu_number); #define BOOT_PERCPU_OFFSET 0 #endif -DEFINE_PER_CPU(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET; +DEFINE_PER_CPU_READ_MOSTLY(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET; EXPORT_PER_CPU_SYMBOL(this_cpu_off); unsigned long __per_cpu_offset[NR_CPUS] __read_mostly = { diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 4d2128ac70bd..a03ec604ceed 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -99,7 +99,7 @@ EXPORT_PER_CPU_SYMBOL(cpu_core_map); DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map); /* Per CPU bogomips and other parameters */ -DEFINE_PER_CPU_SHARED_ALIGNED(struct cpuinfo_x86, cpu_info); +DEFINE_PER_CPU_READ_MOSTLY(struct cpuinfo_x86, cpu_info); EXPORT_PER_CPU_SYMBOL(cpu_info); atomic_t init_deasserted; -- cgit v1.2.2 From 6d24c5f72dfb26e5fa7f02fa9266dfdbae41adba Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Tue, 4 Nov 2014 08:50:18 +0000 Subject: x86-64: Handle PC-relative relocations on per-CPU data This is in preparation of using RIP-relative addressing in many of the per-CPU accesses. Signed-off-by: Jan Beulich Link: http://lkml.kernel.org/r/5458A15A0200007800044A9A@mail.emea.novell.com Signed-off-by: Thomas Gleixner --- arch/x86/boot/compressed/misc.c | 14 +++++++++++++- arch/x86/tools/relocs.c | 36 +++++++++++++++++++++++++++--------- 2 files changed, 40 insertions(+), 10 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index 57ab74df7eea..644abd767c12 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -260,7 +260,7 @@ static void handle_relocations(void *output, unsigned long output_len) /* * Process relocations: 32 bit relocations first then 64 bit after. - * Two sets of binary relocations are added to the end of the kernel + * Three sets of binary relocations are added to the end of the kernel * before compression. Each relocation table entry is the kernel * address of the location which needs to be updated stored as a * 32-bit value which is sign extended to 64 bits. @@ -270,6 +270,8 @@ static void handle_relocations(void *output, unsigned long output_len) * kernel bits... * 0 - zero terminator for 64 bit relocations * 64 bit relocation repeated + * 0 - zero terminator for inverse 32 bit relocations + * 32 bit inverse relocation repeated * 0 - zero terminator for 32 bit relocations * 32 bit relocation repeated * @@ -286,6 +288,16 @@ static void handle_relocations(void *output, unsigned long output_len) *(uint32_t *)ptr += delta; } #ifdef CONFIG_X86_64 + while (*--reloc) { + long extended = *reloc; + extended += map; + + ptr = (unsigned long)extended; + if (ptr < min_addr || ptr > max_addr) + error("inverse 32-bit relocation outside of kernel!\n"); + + *(int32_t *)ptr -= delta; + } for (reloc--; *reloc; reloc--) { long extended = *reloc; extended += map; diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c index a5efb21d5228..0c2fae8d929d 100644 --- a/arch/x86/tools/relocs.c +++ b/arch/x86/tools/relocs.c @@ -20,7 +20,10 @@ struct relocs { static struct relocs relocs16; static struct relocs relocs32; +#if ELF_BITS == 64 +static struct relocs relocs32neg; static struct relocs relocs64; +#endif struct section { Elf_Shdr shdr; @@ -762,11 +765,16 @@ static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym, switch (r_type) { case R_X86_64_NONE: + /* NONE can be ignored. */ + break; + case R_X86_64_PC32: /* - * NONE can be ignored and PC relative relocations don't - * need to be adjusted. + * PC relative relocations don't need to be adjusted unless + * referencing a percpu symbol. */ + if (is_percpu_sym(sym, symname)) + add_reloc(&relocs32neg, offset); break; case R_X86_64_32: @@ -986,7 +994,10 @@ static void emit_relocs(int as_text, int use_real_mode) /* Order the relocations for more efficient processing */ sort_relocs(&relocs16); sort_relocs(&relocs32); +#if ELF_BITS == 64 + sort_relocs(&relocs32neg); sort_relocs(&relocs64); +#endif /* Print the relocations */ if (as_text) { @@ -1007,14 +1018,21 @@ static void emit_relocs(int as_text, int use_real_mode) for (i = 0; i < relocs32.count; i++) write_reloc(relocs32.offset[i], stdout); } else { - if (ELF_BITS == 64) { - /* Print a stop */ - write_reloc(0, stdout); +#if ELF_BITS == 64 + /* Print a stop */ + write_reloc(0, stdout); - /* Now print each relocation */ - for (i = 0; i < relocs64.count; i++) - write_reloc(relocs64.offset[i], stdout); - } + /* Now print each relocation */ + for (i = 0; i < relocs64.count; i++) + write_reloc(relocs64.offset[i], stdout); + + /* Print a stop */ + write_reloc(0, stdout); + + /* Now print each inverse 32-bit relocation */ + for (i = 0; i < relocs32neg.count; i++) + write_reloc(relocs32neg.offset[i], stdout); +#endif /* Print a stop */ write_reloc(0, stdout); -- cgit v1.2.2 From 97b67ae559947f1e208439a1bf6a734da3087006 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Tue, 4 Nov 2014 08:50:48 +0000 Subject: x86-64: Use RIP-relative addressing for most per-CPU accesses Observing that per-CPU data (in the SMP case) is reachable by exploiting 64-bit address wraparound (building on the default kernel load address being at 16Mb), the one byte shorter RIP-relative addressing form can be used for most per-CPU accesses. The one exception are the "stable" reads, where the use of the "P" operand modifier prevents the compiler from using RIP-relative addressing, but is unavoidable due to the use of the "p" constraint (side note: with gcc 4.9.x the intended effect of this isn't being achieved anymore, see gcc bug 63637). With the dependency on the minimum kernel load address, arbitrarily low values for CONFIG_PHYSICAL_START are now no longer possible. A link time assertion is being added, directing to the need to increase that value when it triggers. Signed-off-by: Jan Beulich Link: http://lkml.kernel.org/r/5458A1780200007800044A9D@mail.emea.novell.com Signed-off-by: Thomas Gleixner --- arch/x86/include/asm/percpu.h | 59 ++++++++++++++++++++++++++++++++----------- arch/x86/kernel/vmlinux.lds.S | 2 ++ 2 files changed, 46 insertions(+), 15 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h index 74da3178d776..e0ba66ca68c6 100644 --- a/arch/x86/include/asm/percpu.h +++ b/arch/x86/include/asm/percpu.h @@ -64,7 +64,7 @@ #define __percpu_prefix "" #endif -#define __percpu_arg(x) __percpu_prefix "%P" #x +#define __percpu_arg(x) __percpu_prefix "%" #x /* * Initialized pointers to per-cpu variables needed for the boot @@ -179,29 +179,58 @@ do { \ } \ } while (0) -#define percpu_from_op(op, var, constraint) \ +#define percpu_from_op(op, var) \ ({ \ typeof(var) pfo_ret__; \ switch (sizeof(var)) { \ case 1: \ asm(op "b "__percpu_arg(1)",%0" \ : "=q" (pfo_ret__) \ - : constraint); \ + : "m" (var)); \ break; \ case 2: \ asm(op "w "__percpu_arg(1)",%0" \ : "=r" (pfo_ret__) \ - : constraint); \ + : "m" (var)); \ break; \ case 4: \ asm(op "l "__percpu_arg(1)",%0" \ : "=r" (pfo_ret__) \ - : constraint); \ + : "m" (var)); \ break; \ case 8: \ asm(op "q "__percpu_arg(1)",%0" \ : "=r" (pfo_ret__) \ - : constraint); \ + : "m" (var)); \ + break; \ + default: __bad_percpu_size(); \ + } \ + pfo_ret__; \ +}) + +#define percpu_stable_op(op, var) \ +({ \ + typeof(var) pfo_ret__; \ + switch (sizeof(var)) { \ + case 1: \ + asm(op "b "__percpu_arg(P1)",%0" \ + : "=q" (pfo_ret__) \ + : "p" (&(var))); \ + break; \ + case 2: \ + asm(op "w "__percpu_arg(P1)",%0" \ + : "=r" (pfo_ret__) \ + : "p" (&(var))); \ + break; \ + case 4: \ + asm(op "l "__percpu_arg(P1)",%0" \ + : "=r" (pfo_ret__) \ + : "p" (&(var))); \ + break; \ + case 8: \ + asm(op "q "__percpu_arg(P1)",%0" \ + : "=r" (pfo_ret__) \ + : "p" (&(var))); \ break; \ default: __bad_percpu_size(); \ } \ @@ -359,11 +388,11 @@ do { \ * per-thread variables implemented as per-cpu variables and thus * stable for the duration of the respective task. */ -#define this_cpu_read_stable(var) percpu_from_op("mov", var, "p" (&(var))) +#define this_cpu_read_stable(var) percpu_stable_op("mov", var) -#define raw_cpu_read_1(pcp) percpu_from_op("mov", (pcp), "m"(pcp)) -#define raw_cpu_read_2(pcp) percpu_from_op("mov", (pcp), "m"(pcp)) -#define raw_cpu_read_4(pcp) percpu_from_op("mov", (pcp), "m"(pcp)) +#define raw_cpu_read_1(pcp) percpu_from_op("mov", pcp) +#define raw_cpu_read_2(pcp) percpu_from_op("mov", pcp) +#define raw_cpu_read_4(pcp) percpu_from_op("mov", pcp) #define raw_cpu_write_1(pcp, val) percpu_to_op("mov", (pcp), val) #define raw_cpu_write_2(pcp, val) percpu_to_op("mov", (pcp), val) @@ -381,9 +410,9 @@ do { \ #define raw_cpu_xchg_2(pcp, val) percpu_xchg_op(pcp, val) #define raw_cpu_xchg_4(pcp, val) percpu_xchg_op(pcp, val) -#define this_cpu_read_1(pcp) percpu_from_op("mov", (pcp), "m"(pcp)) -#define this_cpu_read_2(pcp) percpu_from_op("mov", (pcp), "m"(pcp)) -#define this_cpu_read_4(pcp) percpu_from_op("mov", (pcp), "m"(pcp)) +#define this_cpu_read_1(pcp) percpu_from_op("mov", pcp) +#define this_cpu_read_2(pcp) percpu_from_op("mov", pcp) +#define this_cpu_read_4(pcp) percpu_from_op("mov", pcp) #define this_cpu_write_1(pcp, val) percpu_to_op("mov", (pcp), val) #define this_cpu_write_2(pcp, val) percpu_to_op("mov", (pcp), val) #define this_cpu_write_4(pcp, val) percpu_to_op("mov", (pcp), val) @@ -435,7 +464,7 @@ do { \ * 32 bit must fall back to generic operations. */ #ifdef CONFIG_X86_64 -#define raw_cpu_read_8(pcp) percpu_from_op("mov", (pcp), "m"(pcp)) +#define raw_cpu_read_8(pcp) percpu_from_op("mov", pcp) #define raw_cpu_write_8(pcp, val) percpu_to_op("mov", (pcp), val) #define raw_cpu_add_8(pcp, val) percpu_add_op((pcp), val) #define raw_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val) @@ -444,7 +473,7 @@ do { \ #define raw_cpu_xchg_8(pcp, nval) percpu_xchg_op(pcp, nval) #define raw_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval) -#define this_cpu_read_8(pcp) percpu_from_op("mov", (pcp), "m"(pcp)) +#define this_cpu_read_8(pcp) percpu_from_op("mov", pcp) #define this_cpu_write_8(pcp, val) percpu_to_op("mov", (pcp), val) #define this_cpu_add_8(pcp, val) percpu_add_op((pcp), val) #define this_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val) diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 49edf2dd3613..00bf300fd846 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -186,6 +186,8 @@ SECTIONS * start another segment - init. */ PERCPU_VADDR(INTERNODE_CACHE_BYTES, 0, :percpu) + ASSERT(SIZEOF(.data..percpu) < CONFIG_PHYSICAL_START, + "per-CPU data too large - increase CONFIG_PHYSICAL_START") #endif INIT_TEXT_SECTION(PAGE_SIZE) -- cgit v1.2.2