diff options
Diffstat (limited to 'arch/x86/lib')
| -rw-r--r-- | arch/x86/lib/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/lib/checksum_32.S | 7 | ||||
| -rw-r--r-- | arch/x86/lib/cmdline.c | 105 | ||||
| -rw-r--r-- | arch/x86/lib/delay.c | 7 | ||||
| -rw-r--r-- | arch/x86/lib/getuser.S | 10 | ||||
| -rw-r--r-- | arch/x86/lib/retpoline.S | 48 |
6 files changed, 175 insertions, 3 deletions
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index f2587888d987..12a34d15b648 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -21,6 +21,7 @@ lib-y += usercopy_$(BITS).o usercopy.o getuser.o putuser.o lib-y += memcpy_$(BITS).o lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o +lib-$(CONFIG_RETPOLINE) += retpoline.o obj-y += msr.o msr-reg.o msr-reg-export.o diff --git a/arch/x86/lib/checksum_32.S b/arch/x86/lib/checksum_32.S index c1e623209853..90353a26ed95 100644 --- a/arch/x86/lib/checksum_32.S +++ b/arch/x86/lib/checksum_32.S @@ -28,7 +28,8 @@ #include <linux/linkage.h> #include <asm/errno.h> #include <asm/asm.h> - +#include <asm/nospec-branch.h> + /* * computes a partial checksum, e.g. for TCP/UDP fragments */ @@ -155,7 +156,7 @@ ENTRY(csum_partial) negl %ebx lea 45f(%ebx,%ebx,2), %ebx testl %esi, %esi - jmp *%ebx + JMP_NOSPEC %ebx # Handle 2-byte-aligned regions 20: addw (%esi), %ax @@ -437,7 +438,7 @@ ENTRY(csum_partial_copy_generic) andl $-32,%edx lea 3f(%ebx,%ebx), %ebx testl %esi, %esi - jmp *%ebx + JMP_NOSPEC %ebx 1: addl $64,%esi addl $64,%edi SRC(movb -32(%edx),%bl) ; SRC(movb (%edx),%bl) diff --git a/arch/x86/lib/cmdline.c b/arch/x86/lib/cmdline.c index 422db000d727..a744506856b1 100644 --- a/arch/x86/lib/cmdline.c +++ b/arch/x86/lib/cmdline.c @@ -82,3 +82,108 @@ int cmdline_find_option_bool(const char *cmdline, const char *option) return 0; /* Buffer overrun */ } + +/* + * Find a non-boolean option (i.e. option=argument). In accordance with + * standard Linux practice, if this option is repeated, this returns the + * last instance on the command line. + * + * @cmdline: the cmdline string + * @max_cmdline_size: the maximum size of cmdline + * @option: option string to look for + * @buffer: memory buffer to return the option argument + * @bufsize: size of the supplied memory buffer + * + * Returns the length of the argument (regardless of if it was + * truncated to fit in the buffer), or -1 on not found. + */ +static int +__cmdline_find_option(const char *cmdline, int max_cmdline_size, + const char *option, char *buffer, int bufsize) +{ + char c; + int pos = 0, len = -1; + const char *opptr = NULL; + char *bufptr = buffer; + enum { + st_wordstart = 0, /* Start of word/after whitespace */ + st_wordcmp, /* Comparing this word */ + st_wordskip, /* Miscompare, skip */ + st_bufcpy, /* Copying this to buffer */ + } state = st_wordstart; + + if (!cmdline) + return -1; /* No command line */ + + /* + * This 'pos' check ensures we do not overrun + * a non-NULL-terminated 'cmdline' + */ + while (pos++ < max_cmdline_size) { + c = *(char *)cmdline++; + if (!c) + break; + + switch (state) { + case st_wordstart: + if (myisspace(c)) + break; + + state = st_wordcmp; + opptr = option; + /* fall through */ + + case st_wordcmp: + if ((c == '=') && !*opptr) { + /* + * We matched all the way to the end of the + * option we were looking for, prepare to + * copy the argument. + */ + len = 0; + bufptr = buffer; + state = st_bufcpy; + break; + } else if (c == *opptr++) { + /* + * We are currently matching, so continue + * to the next character on the cmdline. + */ + break; + } + state = st_wordskip; + /* fall through */ + + case st_wordskip: + if (myisspace(c)) + state = st_wordstart; + break; + + case st_bufcpy: + if (myisspace(c)) { + state = st_wordstart; + } else { + /* + * Increment len, but don't overrun the + * supplied buffer and leave room for the + * NULL terminator. + */ + if (++len < bufsize) + *bufptr++ = c; + } + break; + } + } + + if (bufsize) + *bufptr = '\0'; + + return len; +} + +int cmdline_find_option(const char *cmdline, const char *option, char *buffer, + int bufsize) +{ + return __cmdline_find_option(cmdline, COMMAND_LINE_SIZE, option, + buffer, bufsize); +} diff --git a/arch/x86/lib/delay.c b/arch/x86/lib/delay.c index e912b2f6d36e..45772560aceb 100644 --- a/arch/x86/lib/delay.c +++ b/arch/x86/lib/delay.c @@ -93,6 +93,13 @@ static void delay_mwaitx(unsigned long __loops) { u64 start, end, delay, loops = __loops; + /* + * Timer value of 0 causes MWAITX to wait indefinitely, unless there + * is a store on the memory monitored by MONITORX. + */ + if (loops == 0) + return; + start = rdtsc_ordered(); for (;;) { diff --git a/arch/x86/lib/getuser.S b/arch/x86/lib/getuser.S index 46668cda4ffd..490b2ee4e4bb 100644 --- a/arch/x86/lib/getuser.S +++ b/arch/x86/lib/getuser.S @@ -38,6 +38,8 @@ ENTRY(__get_user_1) GET_THREAD_INFO(%_ASM_DX) cmp TI_addr_limit(%_ASM_DX),%_ASM_AX jae bad_get_user + sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */ + and %_ASM_DX, %_ASM_AX ASM_STAC 1: movzbl (%_ASM_AX),%edx xor %eax,%eax @@ -51,6 +53,8 @@ ENTRY(__get_user_2) GET_THREAD_INFO(%_ASM_DX) cmp TI_addr_limit(%_ASM_DX),%_ASM_AX jae bad_get_user + sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */ + and %_ASM_DX, %_ASM_AX ASM_STAC 2: movzwl -1(%_ASM_AX),%edx xor %eax,%eax @@ -64,6 +68,8 @@ ENTRY(__get_user_4) GET_THREAD_INFO(%_ASM_DX) cmp TI_addr_limit(%_ASM_DX),%_ASM_AX jae bad_get_user + sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */ + and %_ASM_DX, %_ASM_AX ASM_STAC 3: movl -3(%_ASM_AX),%edx xor %eax,%eax @@ -78,6 +84,8 @@ ENTRY(__get_user_8) GET_THREAD_INFO(%_ASM_DX) cmp TI_addr_limit(%_ASM_DX),%_ASM_AX jae bad_get_user + sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */ + and %_ASM_DX, %_ASM_AX ASM_STAC 4: movq -7(%_ASM_AX),%rdx xor %eax,%eax @@ -89,6 +97,8 @@ ENTRY(__get_user_8) GET_THREAD_INFO(%_ASM_DX) cmp TI_addr_limit(%_ASM_DX),%_ASM_AX jae bad_get_user_8 + sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */ + and %_ASM_DX, %_ASM_AX ASM_STAC 4: movl -7(%_ASM_AX),%edx 5: movl -3(%_ASM_AX),%ecx diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S new file mode 100644 index 000000000000..3d06b482ebc7 --- /dev/null +++ b/arch/x86/lib/retpoline.S @@ -0,0 +1,48 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#include <linux/stringify.h> +#include <linux/linkage.h> +#include <asm/dwarf2.h> +#include <asm/cpufeature.h> +#include <asm/alternative-asm.h> +#include <asm-generic/export.h> +#include <asm/nospec-branch.h> + +.macro THUNK reg + .section .text.__x86.indirect_thunk + +ENTRY(__x86_indirect_thunk_\reg) + CFI_STARTPROC + JMP_NOSPEC %\reg + CFI_ENDPROC +ENDPROC(__x86_indirect_thunk_\reg) +.endm + +/* + * Despite being an assembler file we can't just use .irp here + * because __KSYM_DEPS__ only uses the C preprocessor and would + * only see one instance of "__x86_indirect_thunk_\reg" rather + * than one per register with the correct names. So we do it + * the simple and nasty way... + */ +#define __EXPORT_THUNK(sym) _ASM_NOKPROBE(sym); EXPORT_SYMBOL(sym) +#define EXPORT_THUNK(reg) __EXPORT_THUNK(__x86_indirect_thunk_ ## reg) +#define GENERATE_THUNK(reg) THUNK reg ; EXPORT_THUNK(reg) + +GENERATE_THUNK(_ASM_AX) +GENERATE_THUNK(_ASM_BX) +GENERATE_THUNK(_ASM_CX) +GENERATE_THUNK(_ASM_DX) +GENERATE_THUNK(_ASM_SI) +GENERATE_THUNK(_ASM_DI) +GENERATE_THUNK(_ASM_BP) +#ifdef CONFIG_64BIT +GENERATE_THUNK(r8) +GENERATE_THUNK(r9) +GENERATE_THUNK(r10) +GENERATE_THUNK(r11) +GENERATE_THUNK(r12) +GENERATE_THUNK(r13) +GENERATE_THUNK(r14) +GENERATE_THUNK(r15) +#endif |