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-rw-r--r--Documentation/x86/x86_64/mm.txt6
-rw-r--r--arch/x86/Kconfig10
-rw-r--r--arch/x86/kernel/vmlinux.lds.S6
-rw-r--r--arch/x86/mm/fault.c55
-rw-r--r--arch/x86/mm/kaslr.c94
5 files changed, 66 insertions, 105 deletions
diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt
index 804f9426ed17..6cbe652d7a49 100644
--- a/Documentation/x86/x86_64/mm.txt
+++ b/Documentation/x86/x86_64/mm.txt
@@ -72,7 +72,7 @@ Complete virtual memory map with 5-level page tables
Notes:
- With 56-bit addresses, user-space memory gets expanded by a factor of 512x,
- from 0.125 PB to 64 PB. All kernel mappings shift down to the -64 PT starting
+ from 0.125 PB to 64 PB. All kernel mappings shift down to the -64 PB starting
offset and many of the regions expand to support the much larger physical
memory supported.
@@ -83,7 +83,7 @@ Notes:
0000000000000000 | 0 | 00ffffffffffffff | 64 PB | user-space virtual memory, different per mm
__________________|____________|__________________|_________|___________________________________________________________
| | | |
- 0000800000000000 | +64 PB | ffff7fffffffffff | ~16K PB | ... huge, still almost 64 bits wide hole of non-canonical
+ 0100000000000000 | +64 PB | feffffffffffffff | ~16K PB | ... huge, still almost 64 bits wide hole of non-canonical
| | | | virtual memory addresses up to the -64 PB
| | | | starting offset of kernel mappings.
__________________|____________|__________________|_________|___________________________________________________________
@@ -99,7 +99,7 @@ ____________________________________________________________|___________________
ffd2000000000000 | -11.5 PB | ffd3ffffffffffff | 0.5 PB | ... unused hole
ffd4000000000000 | -11 PB | ffd5ffffffffffff | 0.5 PB | virtual memory map (vmemmap_base)
ffd6000000000000 | -10.5 PB | ffdeffffffffffff | 2.25 PB | ... unused hole
- ffdf000000000000 | -8.25 PB | fffffdffffffffff | ~8 PB | KASAN shadow memory
+ ffdf000000000000 | -8.25 PB | fffffbffffffffff | ~8 PB | KASAN shadow memory
__________________|____________|__________________|_________|____________________________________________________________
|
| Identical layout to the 47-bit one from here on:
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 62fc3fda1a05..bd6f93ce0633 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1606,12 +1606,9 @@ config ARCH_FLATMEM_ENABLE
depends on X86_32 && !NUMA
config ARCH_DISCONTIGMEM_ENABLE
- def_bool y
- depends on NUMA && X86_32
-
-config ARCH_DISCONTIGMEM_DEFAULT
- def_bool y
+ def_bool n
depends on NUMA && X86_32
+ depends on BROKEN
config ARCH_SPARSEMEM_ENABLE
def_bool y
@@ -1620,8 +1617,7 @@ config ARCH_SPARSEMEM_ENABLE
select SPARSEMEM_VMEMMAP_ENABLE if X86_64
config ARCH_SPARSEMEM_DEFAULT
- def_bool y
- depends on X86_64
+ def_bool X86_64 || (NUMA && X86_32)
config ARCH_SELECT_MEMORY_MODEL
def_bool y
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index a5127b2c195f..834659288ba9 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -141,11 +141,11 @@ SECTIONS
*(.text.__x86.indirect_thunk)
__indirect_thunk_end = .;
#endif
-
- /* End of text section */
- _etext = .;
} :text = 0x9090
+ /* End of text section */
+ _etext = .;
+
NOTES :text :note
EXCEPTION_TABLE(16) :text = 0x9090
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 667f1da36208..bd20de9db1a8 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -359,8 +359,6 @@ static noinline int vmalloc_fault(unsigned long address)
if (!(address >= VMALLOC_START && address < VMALLOC_END))
return -1;
- WARN_ON_ONCE(in_nmi());
-
/*
* Copy kernel mappings over when needed. This can also
* happen within a race in page table update. In the later
@@ -603,24 +601,9 @@ static void show_ldttss(const struct desc_ptr *gdt, const char *name, u16 index)
name, index, addr, (desc.limit0 | (desc.limit1 << 16)));
}
-/*
- * This helper function transforms the #PF error_code bits into
- * "[PROT] [USER]" type of descriptive, almost human-readable error strings:
- */
-static void err_str_append(unsigned long error_code, char *buf, unsigned long mask, const char *txt)
-{
- if (error_code & mask) {
- if (buf[0])
- strcat(buf, " ");
- strcat(buf, txt);
- }
-}
-
static void
show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long address)
{
- char err_txt[64];
-
if (!oops_may_print())
return;
@@ -644,31 +627,29 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long ad
from_kuid(&init_user_ns, current_uid()));
}
- pr_alert("BUG: unable to handle kernel %s at %px\n",
- address < PAGE_SIZE ? "NULL pointer dereference" : "paging request",
- (void *)address);
-
- err_txt[0] = 0;
-
- /*
- * Note: length of these appended strings including the separation space and the
- * zero delimiter must fit into err_txt[].
- */
- err_str_append(error_code, err_txt, X86_PF_PROT, "[PROT]" );
- err_str_append(error_code, err_txt, X86_PF_WRITE, "[WRITE]");
- err_str_append(error_code, err_txt, X86_PF_USER, "[USER]" );
- err_str_append(error_code, err_txt, X86_PF_RSVD, "[RSVD]" );
- err_str_append(error_code, err_txt, X86_PF_INSTR, "[INSTR]");
- err_str_append(error_code, err_txt, X86_PF_PK, "[PK]" );
-
- pr_alert("#PF error: %s\n", error_code ? err_txt : "[normal kernel read fault]");
+ if (address < PAGE_SIZE && !user_mode(regs))
+ pr_alert("BUG: kernel NULL pointer dereference, address: %px\n",
+ (void *)address);
+ else
+ pr_alert("BUG: unable to handle page fault for address: %px\n",
+ (void *)address);
+
+ pr_alert("#PF: %s %s in %s mode\n",
+ (error_code & X86_PF_USER) ? "user" : "supervisor",
+ (error_code & X86_PF_INSTR) ? "instruction fetch" :
+ (error_code & X86_PF_WRITE) ? "write access" :
+ "read access",
+ user_mode(regs) ? "user" : "kernel");
+ pr_alert("#PF: error_code(0x%04lx) - %s\n", error_code,
+ !(error_code & X86_PF_PROT) ? "not-present page" :
+ (error_code & X86_PF_RSVD) ? "reserved bit violation" :
+ (error_code & X86_PF_PK) ? "protection keys violation" :
+ "permissions violation");
if (!(error_code & X86_PF_USER) && user_mode(regs)) {
struct desc_ptr idt, gdt;
u16 ldtr, tr;
- pr_alert("This was a system access from user code\n");
-
/*
* This can happen for quite a few reasons. The more obvious
* ones are faults accessing the GDT, or LDT. Perhaps
diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index d669c5e797e0..dc3f058bdf9b 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -125,10 +125,7 @@ void __init kernel_randomize_memory(void)
*/
entropy = remain_entropy / (ARRAY_SIZE(kaslr_regions) - i);
prandom_bytes_state(&rand_state, &rand, sizeof(rand));
- if (pgtable_l5_enabled())
- entropy = (rand % (entropy + 1)) & P4D_MASK;
- else
- entropy = (rand % (entropy + 1)) & PUD_MASK;
+ entropy = (rand % (entropy + 1)) & PUD_MASK;
vaddr += entropy;
*kaslr_regions[i].base = vaddr;
@@ -137,84 +134,71 @@ void __init kernel_randomize_memory(void)
* randomization alignment.
*/
vaddr += get_padding(&kaslr_regions[i]);
- if (pgtable_l5_enabled())
- vaddr = round_up(vaddr + 1, P4D_SIZE);
- else
- vaddr = round_up(vaddr + 1, PUD_SIZE);
+ vaddr = round_up(vaddr + 1, PUD_SIZE);
remain_entropy -= entropy;
}
}
static void __meminit init_trampoline_pud(void)
{
- unsigned long paddr, paddr_next;
+ pud_t *pud_page_tramp, *pud, *pud_tramp;
+ p4d_t *p4d_page_tramp, *p4d, *p4d_tramp;
+ unsigned long paddr, vaddr;
pgd_t *pgd;
- pud_t *pud_page, *pud_page_tramp;
- int i;
pud_page_tramp = alloc_low_page();
+ /*
+ * There are two mappings for the low 1MB area, the direct mapping
+ * and the 1:1 mapping for the real mode trampoline:
+ *
+ * Direct mapping: virt_addr = phys_addr + PAGE_OFFSET
+ * 1:1 mapping: virt_addr = phys_addr
+ */
paddr = 0;
- pgd = pgd_offset_k((unsigned long)__va(paddr));
- pud_page = (pud_t *) pgd_page_vaddr(*pgd);
-
- for (i = pud_index(paddr); i < PTRS_PER_PUD; i++, paddr = paddr_next) {
- pud_t *pud, *pud_tramp;
- unsigned long vaddr = (unsigned long)__va(paddr);
+ vaddr = (unsigned long)__va(paddr);
+ pgd = pgd_offset_k(vaddr);
- pud_tramp = pud_page_tramp + pud_index(paddr);
- pud = pud_page + pud_index(vaddr);
- paddr_next = (paddr & PUD_MASK) + PUD_SIZE;
-
- *pud_tramp = *pud;
- }
+ p4d = p4d_offset(pgd, vaddr);
+ pud = pud_offset(p4d, vaddr);
- set_pgd(&trampoline_pgd_entry,
- __pgd(_KERNPG_TABLE | __pa(pud_page_tramp)));
-}
-
-static void __meminit init_trampoline_p4d(void)
-{
- unsigned long paddr, paddr_next;
- pgd_t *pgd;
- p4d_t *p4d_page, *p4d_page_tramp;
- int i;
+ pud_tramp = pud_page_tramp + pud_index(paddr);
+ *pud_tramp = *pud;
- p4d_page_tramp = alloc_low_page();
-
- paddr = 0;
- pgd = pgd_offset_k((unsigned long)__va(paddr));
- p4d_page = (p4d_t *) pgd_page_vaddr(*pgd);
-
- for (i = p4d_index(paddr); i < PTRS_PER_P4D; i++, paddr = paddr_next) {
- p4d_t *p4d, *p4d_tramp;
- unsigned long vaddr = (unsigned long)__va(paddr);
+ if (pgtable_l5_enabled()) {
+ p4d_page_tramp = alloc_low_page();
p4d_tramp = p4d_page_tramp + p4d_index(paddr);
- p4d = p4d_page + p4d_index(vaddr);
- paddr_next = (paddr & P4D_MASK) + P4D_SIZE;
- *p4d_tramp = *p4d;
- }
+ set_p4d(p4d_tramp,
+ __p4d(_KERNPG_TABLE | __pa(pud_page_tramp)));
- set_pgd(&trampoline_pgd_entry,
- __pgd(_KERNPG_TABLE | __pa(p4d_page_tramp)));
+ set_pgd(&trampoline_pgd_entry,
+ __pgd(_KERNPG_TABLE | __pa(p4d_page_tramp)));
+ } else {
+ set_pgd(&trampoline_pgd_entry,
+ __pgd(_KERNPG_TABLE | __pa(pud_page_tramp)));
+ }
}
/*
- * Create PGD aligned trampoline table to allow real mode initialization
- * of additional CPUs. Consume only 1 low memory page.
+ * The real mode trampoline, which is required for bootstrapping CPUs
+ * occupies only a small area under the low 1MB. See reserve_real_mode()
+ * for details.
+ *
+ * If KASLR is disabled the first PGD entry of the direct mapping is copied
+ * to map the real mode trampoline.
+ *
+ * If KASLR is enabled, copy only the PUD which covers the low 1MB
+ * area. This limits the randomization granularity to 1GB for both 4-level
+ * and 5-level paging.
*/
void __meminit init_trampoline(void)
{
-
if (!kaslr_memory_enabled()) {
init_trampoline_default();
return;
}
- if (pgtable_l5_enabled())
- init_trampoline_p4d();
- else
- init_trampoline_pud();
+ init_trampoline_pud();
}
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-16 14:04:44 +0100