Misc fixes:

- Fix an UV boot crash,
 - Skip spurious ENDBR generation on _THIS_IP_,
 - Fix ENDBR use in putuser() asm methods,
 - Fix corner case boot crashes on 5-level paging,
 - and fix a false positive WARNING on LTO kernels.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-urgent-2023-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Ingo Molnar:
 "Misc fixes:

   - Fix an UV boot crash

   - Skip spurious ENDBR generation on _THIS_IP_

   - Fix ENDBR use in putuser() asm methods

   - Fix corner case boot crashes on 5-level paging

   - and fix a false positive WARNING on LTO kernels"

* tag 'x86-urgent-2023-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/purgatory: Remove LTO flags
  x86/boot/compressed: Reserve more memory for page tables
  x86/ibt: Avoid duplicate ENDBR in __put_user_nocheck*()
  x86/ibt: Suppress spurious ENDBR
  x86/platform/uv: Use alternate source for socket to node data
This commit is contained in:
Linus Torvalds 2023-09-17 11:13:37 -07:00
commit e789286468
7 changed files with 62 additions and 25 deletions

View file

@ -59,6 +59,14 @@ static void *alloc_pgt_page(void *context)
return NULL;
}
/* Consumed more tables than expected? */
if (pages->pgt_buf_offset == BOOT_PGT_SIZE_WARN) {
debug_putstr("pgt_buf running low in " __FILE__ "\n");
debug_putstr("Need to raise BOOT_PGT_SIZE?\n");
debug_putaddr(pages->pgt_buf_offset);
debug_putaddr(pages->pgt_buf_size);
}
entry = pages->pgt_buf + pages->pgt_buf_offset;
pages->pgt_buf_offset += PAGE_SIZE;

View file

@ -40,23 +40,40 @@
#ifdef CONFIG_X86_64
# define BOOT_STACK_SIZE 0x4000
# define BOOT_INIT_PGT_SIZE (6*4096)
# ifdef CONFIG_RANDOMIZE_BASE
/*
* Assuming all cross the 512GB boundary:
* 1 page for level4
* (2+2)*4 pages for kernel, param, cmd_line, and randomized kernel
* 2 pages for first 2M (video RAM: CONFIG_X86_VERBOSE_BOOTUP).
* Total is 19 pages.
* Used by decompressor's startup_32() to allocate page tables for identity
* mapping of the 4G of RAM in 4-level paging mode:
* - 1 level4 table;
* - 1 level3 table;
* - 4 level2 table that maps everything with 2M pages;
*
* The additional level5 table needed for 5-level paging is allocated from
* trampoline_32bit memory.
*/
# ifdef CONFIG_X86_VERBOSE_BOOTUP
# define BOOT_PGT_SIZE (19*4096)
# else /* !CONFIG_X86_VERBOSE_BOOTUP */
# define BOOT_PGT_SIZE (17*4096)
# endif
# else /* !CONFIG_RANDOMIZE_BASE */
# define BOOT_PGT_SIZE BOOT_INIT_PGT_SIZE
# endif
# define BOOT_INIT_PGT_SIZE (6*4096)
/*
* Total number of page tables kernel_add_identity_map() can allocate,
* including page tables consumed by startup_32().
*
* Worst-case scenario:
* - 5-level paging needs 1 level5 table;
* - KASLR needs to map kernel, boot_params, cmdline and randomized kernel,
* assuming all of them cross 256T boundary:
* + 4*2 level4 table;
* + 4*2 level3 table;
* + 4*2 level2 table;
* - X86_VERBOSE_BOOTUP needs to map the first 2M (video RAM):
* + 1 level4 table;
* + 1 level3 table;
* + 1 level2 table;
* Total: 28 tables
*
* Add 4 spare table in case decompressor touches anything beyond what is
* accounted above. Warn if it happens.
*/
# define BOOT_PGT_SIZE_WARN (28*4096)
# define BOOT_PGT_SIZE (32*4096)
#else /* !CONFIG_X86_64 */
# define BOOT_STACK_SIZE 0x1000

View file

@ -8,6 +8,14 @@
#undef notrace
#define notrace __attribute__((no_instrument_function))
#ifdef CONFIG_64BIT
/*
* The generic version tends to create spurious ENDBR instructions under
* certain conditions.
*/
#define _THIS_IP_ ({ unsigned long __here; asm ("lea 0(%%rip), %0" : "=r" (__here)); __here; })
#endif
#ifdef CONFIG_X86_32
#define asmlinkage CPP_ASMLINKAGE __attribute__((regparm(0)))
#endif /* CONFIG_X86_32 */

View file

@ -1533,7 +1533,7 @@ static void __init build_socket_tables(void)
{
struct uv_gam_range_entry *gre = uv_gre_table;
int nums, numn, nump;
int cpu, i, lnid;
int i, lnid, apicid;
int minsock = _min_socket;
int maxsock = _max_socket;
int minpnode = _min_pnode;
@ -1584,15 +1584,14 @@ static void __init build_socket_tables(void)
/* Set socket -> node values: */
lnid = NUMA_NO_NODE;
for_each_possible_cpu(cpu) {
int nid = cpu_to_node(cpu);
int apicid, sockid;
for (apicid = 0; apicid < ARRAY_SIZE(__apicid_to_node); apicid++) {
int nid = __apicid_to_node[apicid];
int sockid;
if (lnid == nid)
if ((nid == NUMA_NO_NODE) || (lnid == nid))
continue;
lnid = nid;
apicid = per_cpu(x86_cpu_to_apicid, cpu);
sockid = apicid >> uv_cpuid.socketid_shift;
if (_socket_to_node[sockid - minsock] == SOCK_EMPTY)

View file

@ -56,7 +56,6 @@ SYM_FUNC_END(__put_user_1)
EXPORT_SYMBOL(__put_user_1)
SYM_FUNC_START(__put_user_nocheck_1)
ENDBR
ASM_STAC
2: movb %al,(%_ASM_CX)
xor %ecx,%ecx
@ -76,7 +75,6 @@ SYM_FUNC_END(__put_user_2)
EXPORT_SYMBOL(__put_user_2)
SYM_FUNC_START(__put_user_nocheck_2)
ENDBR
ASM_STAC
4: movw %ax,(%_ASM_CX)
xor %ecx,%ecx
@ -96,7 +94,6 @@ SYM_FUNC_END(__put_user_4)
EXPORT_SYMBOL(__put_user_4)
SYM_FUNC_START(__put_user_nocheck_4)
ENDBR
ASM_STAC
6: movl %eax,(%_ASM_CX)
xor %ecx,%ecx
@ -119,7 +116,6 @@ SYM_FUNC_END(__put_user_8)
EXPORT_SYMBOL(__put_user_8)
SYM_FUNC_START(__put_user_nocheck_8)
ENDBR
ASM_STAC
9: mov %_ASM_AX,(%_ASM_CX)
#ifdef CONFIG_X86_32

View file

@ -19,6 +19,10 @@ CFLAGS_sha256.o := -D__DISABLE_EXPORTS -D__NO_FORTIFY
# optimization flags.
KBUILD_CFLAGS := $(filter-out -fprofile-sample-use=% -fprofile-use=%,$(KBUILD_CFLAGS))
# When LTO is enabled, llvm emits many text sections, which is not supported
# by kexec. Remove -flto=* flags.
KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_LTO),$(KBUILD_CFLAGS))
# When linking purgatory.ro with -r unresolved symbols are not checked,
# also link a purgatory.chk binary without -r to check for unresolved symbols.
PURGATORY_LDFLAGS := -e purgatory_start -z nodefaultlib

View file

@ -2,7 +2,12 @@
#ifndef _LINUX_INSTRUCTION_POINTER_H
#define _LINUX_INSTRUCTION_POINTER_H
#include <asm/linkage.h>
#define _RET_IP_ (unsigned long)__builtin_return_address(0)
#ifndef _THIS_IP_
#define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
#endif
#endif /* _LINUX_INSTRUCTION_POINTER_H */