[GIT PULL] x86/boot changes for v4.11
From: Ingo Molnar
Date: Mon Feb 20 2017 - 06:50:13 EST
Linus,
Please pull the latest x86-boot-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-boot-for-linus
# HEAD: 5773ebfee729acf93b330664eab4c8d77edc2193 x86/kconfig: Remove misleading note regarding hibernation and KASLR
Misc updates: fix e820 error handling, convert page table setup code from assembly
to C, fix kexec environment bug, plus small cleanups.
Thanks,
Ingo
------------------>
Arnd Bergmann (1):
x86/e820/32: Fix e820_search_gap() error handling on x86-32
Boris Ostrovsky (1):
x86/boot/32: Convert the 32-bit pgtable setup code from assembly to C
Dave Jiang (1):
x86/boot: Fix KASLR and memmap= collision
Niklas Cassel (1):
x86/kconfig: Remove misleading note regarding hibernation and KASLR
Wei Yang (1):
x86/e820: Make e820_search_gap() static and remove unused variables
arch/x86/Kconfig | 4 --
arch/x86/boot/boot.h | 1 +
arch/x86/boot/compressed/kaslr.c | 140 +++++++++++++++++++++++++++++++++++++-
arch/x86/boot/string.c | 13 ++++
arch/x86/include/asm/e820.h | 2 -
arch/x86/include/asm/pgtable_32.h | 32 +++++++++
arch/x86/kernel/e820.c | 22 +++---
arch/x86/kernel/head32.c | 62 +++++++++++++++++
arch/x86/kernel/head_32.S | 121 ++------------------------------
9 files changed, 261 insertions(+), 136 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e487493bbd47..4e6dbca03aed 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1994,10 +1994,6 @@ config RANDOMIZE_BASE
theoretically possible, but the implementations are further
limited due to memory layouts.
- If CONFIG_HIBERNATE is also enabled, KASLR is disabled at boot
- time. To enable it, boot with "kaslr" on the kernel command
- line (which will also disable hibernation).
-
If unsure, say N.
# Relocation on x86 needs some additional build support
diff --git a/arch/x86/boot/boot.h b/arch/x86/boot/boot.h
index e5612f3e3b57..9b42b6d1e902 100644
--- a/arch/x86/boot/boot.h
+++ b/arch/x86/boot/boot.h
@@ -333,6 +333,7 @@ size_t strnlen(const char *s, size_t maxlen);
unsigned int atou(const char *s);
unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base);
size_t strlen(const char *s);
+char *strchr(const char *s, int c);
/* tty.c */
void puts(const char *);
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index a66854d99ee1..8b7c9e75edcb 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -11,6 +11,7 @@
*/
#include "misc.h"
#include "error.h"
+#include "../boot.h"
#include <generated/compile.h>
#include <linux/module.h>
@@ -52,15 +53,22 @@ static unsigned long get_boot_seed(void)
#include "../../lib/kaslr.c"
struct mem_vector {
- unsigned long start;
- unsigned long size;
+ unsigned long long start;
+ unsigned long long size;
};
+/* Only supporting at most 4 unusable memmap regions with kaslr */
+#define MAX_MEMMAP_REGIONS 4
+
+static bool memmap_too_large;
+
enum mem_avoid_index {
MEM_AVOID_ZO_RANGE = 0,
MEM_AVOID_INITRD,
MEM_AVOID_CMDLINE,
MEM_AVOID_BOOTPARAMS,
+ MEM_AVOID_MEMMAP_BEGIN,
+ MEM_AVOID_MEMMAP_END = MEM_AVOID_MEMMAP_BEGIN + MAX_MEMMAP_REGIONS - 1,
MEM_AVOID_MAX,
};
@@ -77,6 +85,123 @@ static bool mem_overlaps(struct mem_vector *one, struct mem_vector *two)
return true;
}
+/**
+ * _memparse - Parse a string with mem suffixes into a number
+ * @ptr: Where parse begins
+ * @retptr: (output) Optional pointer to next char after parse completes
+ *
+ * Parses a string into a number. The number stored at @ptr is
+ * potentially suffixed with K, M, G, T, P, E.
+ */
+static unsigned long long _memparse(const char *ptr, char **retptr)
+{
+ char *endptr; /* Local pointer to end of parsed string */
+
+ unsigned long long ret = simple_strtoull(ptr, &endptr, 0);
+
+ switch (*endptr) {
+ case 'E':
+ case 'e':
+ ret <<= 10;
+ case 'P':
+ case 'p':
+ ret <<= 10;
+ case 'T':
+ case 't':
+ ret <<= 10;
+ case 'G':
+ case 'g':
+ ret <<= 10;
+ case 'M':
+ case 'm':
+ ret <<= 10;
+ case 'K':
+ case 'k':
+ ret <<= 10;
+ endptr++;
+ default:
+ break;
+ }
+
+ if (retptr)
+ *retptr = endptr;
+
+ return ret;
+}
+
+static int
+parse_memmap(char *p, unsigned long long *start, unsigned long long *size)
+{
+ char *oldp;
+
+ if (!p)
+ return -EINVAL;
+
+ /* We don't care about this option here */
+ if (!strncmp(p, "exactmap", 8))
+ return -EINVAL;
+
+ oldp = p;
+ *size = _memparse(p, &p);
+ if (p == oldp)
+ return -EINVAL;
+
+ switch (*p) {
+ case '@':
+ /* Skip this region, usable */
+ *start = 0;
+ *size = 0;
+ return 0;
+ case '#':
+ case '$':
+ case '!':
+ *start = _memparse(p + 1, &p);
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static void mem_avoid_memmap(void)
+{
+ char arg[128];
+ int rc;
+ int i;
+ char *str;
+
+ /* See if we have any memmap areas */
+ rc = cmdline_find_option("memmap", arg, sizeof(arg));
+ if (rc <= 0)
+ return;
+
+ i = 0;
+ str = arg;
+ while (str && (i < MAX_MEMMAP_REGIONS)) {
+ int rc;
+ unsigned long long start, size;
+ char *k = strchr(str, ',');
+
+ if (k)
+ *k++ = 0;
+
+ rc = parse_memmap(str, &start, &size);
+ if (rc < 0)
+ break;
+ str = k;
+ /* A usable region that should not be skipped */
+ if (size == 0)
+ continue;
+
+ mem_avoid[MEM_AVOID_MEMMAP_BEGIN + i].start = start;
+ mem_avoid[MEM_AVOID_MEMMAP_BEGIN + i].size = size;
+ i++;
+ }
+
+ /* More than 4 memmaps, fail kaslr */
+ if ((i >= MAX_MEMMAP_REGIONS) && str)
+ memmap_too_large = true;
+}
+
/*
* In theory, KASLR can put the kernel anywhere in the range of [16M, 64T).
* The mem_avoid array is used to store the ranges that need to be avoided
@@ -197,6 +322,9 @@ static void mem_avoid_init(unsigned long input, unsigned long input_size,
/* We don't need to set a mapping for setup_data. */
+ /* Mark the memmap regions we need to avoid */
+ mem_avoid_memmap();
+
#ifdef CONFIG_X86_VERBOSE_BOOTUP
/* Make sure video RAM can be used. */
add_identity_map(0, PMD_SIZE);
@@ -379,6 +507,12 @@ static unsigned long find_random_phys_addr(unsigned long minimum,
int i;
unsigned long addr;
+ /* Check if we had too many memmaps. */
+ if (memmap_too_large) {
+ debug_putstr("Aborted e820 scan (more than 4 memmap= args)!\n");
+ return 0;
+ }
+
/* Make sure minimum is aligned. */
minimum = ALIGN(minimum, CONFIG_PHYSICAL_ALIGN);
@@ -456,7 +590,7 @@ void choose_random_location(unsigned long input,
/* Walk e820 and find a random address. */
random_addr = find_random_phys_addr(min_addr, output_size);
if (!random_addr) {
- warn("KASLR disabled: could not find suitable E820 region!");
+ warn("Physical KASLR disabled: no suitable memory region!");
} else {
/* Update the new physical address location. */
if (*output != random_addr) {
diff --git a/arch/x86/boot/string.c b/arch/x86/boot/string.c
index 9e240fcba784..5457b02fc050 100644
--- a/arch/x86/boot/string.c
+++ b/arch/x86/boot/string.c
@@ -156,3 +156,16 @@ char *strstr(const char *s1, const char *s2)
}
return NULL;
}
+
+/**
+ * strchr - Find the first occurrence of the character c in the string s.
+ * @s: the string to be searched
+ * @c: the character to search for
+ */
+char *strchr(const char *s, int c)
+{
+ while (*s != (char)c)
+ if (*s++ == '\0')
+ return NULL;
+ return (char *)s;
+}
diff --git a/arch/x86/include/asm/e820.h b/arch/x86/include/asm/e820.h
index ec23d8e1297c..67313f3a9874 100644
--- a/arch/x86/include/asm/e820.h
+++ b/arch/x86/include/asm/e820.h
@@ -30,8 +30,6 @@ extern u64 e820_remove_range(u64 start, u64 size, unsigned old_type,
int checktype);
extern void update_e820(void);
extern void e820_setup_gap(void);
-extern int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize,
- unsigned long start_addr, unsigned long long end_addr);
struct setup_data;
extern void parse_e820_ext(u64 phys_addr, u32 data_len);
diff --git a/arch/x86/include/asm/pgtable_32.h b/arch/x86/include/asm/pgtable_32.h
index b6c0b404898a..fbc73360aea0 100644
--- a/arch/x86/include/asm/pgtable_32.h
+++ b/arch/x86/include/asm/pgtable_32.h
@@ -27,6 +27,7 @@ struct vm_area_struct;
extern pgd_t swapper_pg_dir[1024];
extern pgd_t initial_page_table[1024];
+extern pmd_t initial_pg_pmd[];
static inline void pgtable_cache_init(void) { }
static inline void check_pgt_cache(void) { }
@@ -75,4 +76,35 @@ do { \
#define kern_addr_valid(kaddr) (0)
#endif
+/*
+ * This is how much memory in addition to the memory covered up to
+ * and including _end we need mapped initially.
+ * We need:
+ * (KERNEL_IMAGE_SIZE/4096) / 1024 pages (worst case, non PAE)
+ * (KERNEL_IMAGE_SIZE/4096) / 512 + 4 pages (worst case for PAE)
+ *
+ * Modulo rounding, each megabyte assigned here requires a kilobyte of
+ * memory, which is currently unreclaimed.
+ *
+ * This should be a multiple of a page.
+ *
+ * KERNEL_IMAGE_SIZE should be greater than pa(_end)
+ * and small than max_low_pfn, otherwise will waste some page table entries
+ */
+#if PTRS_PER_PMD > 1
+#define PAGE_TABLE_SIZE(pages) (((pages) / PTRS_PER_PMD) + PTRS_PER_PGD)
+#else
+#define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD)
+#endif
+
+/*
+ * Number of possible pages in the lowmem region.
+ *
+ * We shift 2 by 31 instead of 1 by 32 to the left in order to avoid a
+ * gas warning about overflowing shift count when gas has been compiled
+ * with only a host target support using a 32-bit type for internal
+ * representation.
+ */
+#define LOWMEM_PAGES ((((2<<31) - __PAGE_OFFSET) >> PAGE_SHIFT))
+
#endif /* _ASM_X86_PGTABLE_32_H */
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 90e8dde3ec26..b2bbad6ebe4d 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -580,24 +580,19 @@ static void __init update_e820_saved(void)
}
#define MAX_GAP_END 0x100000000ull
/*
- * Search for a gap in the e820 memory space from start_addr to end_addr.
+ * Search for a gap in the e820 memory space from 0 to MAX_GAP_END.
*/
-__init int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize,
- unsigned long start_addr, unsigned long long end_addr)
+static int __init e820_search_gap(unsigned long *gapstart,
+ unsigned long *gapsize)
{
- unsigned long long last;
+ unsigned long long last = MAX_GAP_END;
int i = e820->nr_map;
int found = 0;
- last = (end_addr && end_addr < MAX_GAP_END) ? end_addr : MAX_GAP_END;
-
while (--i >= 0) {
unsigned long long start = e820->map[i].addr;
unsigned long long end = start + e820->map[i].size;
- if (end < start_addr)
- continue;
-
/*
* Since "last" is at most 4GB, we know we'll
* fit in 32 bits if this condition is true
@@ -628,18 +623,19 @@ __init void e820_setup_gap(void)
unsigned long gapstart, gapsize;
int found;
- gapstart = 0x10000000;
gapsize = 0x400000;
- found = e820_search_gap(&gapstart, &gapsize, 0, MAX_GAP_END);
+ found = e820_search_gap(&gapstart, &gapsize);
-#ifdef CONFIG_X86_64
if (!found) {
+#ifdef CONFIG_X86_64
gapstart = (max_pfn << PAGE_SHIFT) + 1024*1024;
printk(KERN_ERR
"e820: cannot find a gap in the 32bit address range\n"
"e820: PCI devices with unassigned 32bit BARs may break!\n");
- }
+#else
+ gapstart = 0x10000000;
#endif
+ }
/*
* e820_reserve_resources_late protect stolen RAM already
diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
index f16c55bfc090..e5fb436a6548 100644
--- a/arch/x86/kernel/head32.c
+++ b/arch/x86/kernel/head32.c
@@ -49,3 +49,65 @@ asmlinkage __visible void __init i386_start_kernel(void)
start_kernel();
}
+
+/*
+ * Initialize page tables. This creates a PDE and a set of page
+ * tables, which are located immediately beyond __brk_base. The variable
+ * _brk_end is set up to point to the first "safe" location.
+ * Mappings are created both at virtual address 0 (identity mapping)
+ * and PAGE_OFFSET for up to _end.
+ *
+ * In PAE mode initial_page_table is statically defined to contain
+ * enough entries to cover the VMSPLIT option (that is the top 1, 2 or 3
+ * entries). The identity mapping is handled by pointing two PGD entries
+ * to the first kernel PMD. Note the upper half of each PMD or PTE are
+ * always zero at this stage.
+ */
+void __init mk_early_pgtbl_32(void)
+{
+#ifdef __pa
+#undef __pa
+#endif
+#define __pa(x) ((unsigned long)(x) - PAGE_OFFSET)
+ pte_t pte, *ptep;
+ int i;
+ unsigned long *ptr;
+ /* Enough space to fit pagetables for the low memory linear map */
+ const unsigned long limit = __pa(_end) +
+ (PAGE_TABLE_SIZE(LOWMEM_PAGES) << PAGE_SHIFT);
+#ifdef CONFIG_X86_PAE
+ pmd_t pl2, *pl2p = (pmd_t *)__pa(initial_pg_pmd);
+#define SET_PL2(pl2, val) { (pl2).pmd = (val); }
+#else
+ pgd_t pl2, *pl2p = (pgd_t *)__pa(initial_page_table);
+#define SET_PL2(pl2, val) { (pl2).pgd = (val); }
+#endif
+
+ ptep = (pte_t *)__pa(__brk_base);
+ pte.pte = PTE_IDENT_ATTR;
+
+ while ((pte.pte & PTE_PFN_MASK) < limit) {
+
+ SET_PL2(pl2, (unsigned long)ptep | PDE_IDENT_ATTR);
+ *pl2p = pl2;
+#ifndef CONFIG_X86_PAE
+ /* Kernel PDE entry */
+ *(pl2p + ((PAGE_OFFSET >> PGDIR_SHIFT))) = pl2;
+#endif
+ for (i = 0; i < PTRS_PER_PTE; i++) {
+ *ptep = pte;
+ pte.pte += PAGE_SIZE;
+ ptep++;
+ }
+
+ pl2p++;
+ }
+
+ ptr = (unsigned long *)__pa(&max_pfn_mapped);
+ /* Can't use pte_pfn() since it's a call with CONFIG_PARAVIRT */
+ *ptr = (pte.pte & PTE_PFN_MASK) >> PAGE_SHIFT;
+
+ ptr = (unsigned long *)__pa(&_brk_end);
+ *ptr = (unsigned long)ptep + PAGE_OFFSET;
+}
+
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index 4e8577d03372..1f85ee8f9439 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -24,6 +24,7 @@
#include <asm/nops.h>
#include <asm/bootparam.h>
#include <asm/export.h>
+#include <asm/pgtable_32.h>
/* Physical address */
#define pa(X) ((X) - __PAGE_OFFSET)
@@ -41,44 +42,10 @@
#define X86_CAPABILITY new_cpu_data+CPUINFO_x86_capability
#define X86_VENDOR_ID new_cpu_data+CPUINFO_x86_vendor_id
-/*
- * This is how much memory in addition to the memory covered up to
- * and including _end we need mapped initially.
- * We need:
- * (KERNEL_IMAGE_SIZE/4096) / 1024 pages (worst case, non PAE)
- * (KERNEL_IMAGE_SIZE/4096) / 512 + 4 pages (worst case for PAE)
- *
- * Modulo rounding, each megabyte assigned here requires a kilobyte of
- * memory, which is currently unreclaimed.
- *
- * This should be a multiple of a page.
- *
- * KERNEL_IMAGE_SIZE should be greater than pa(_end)
- * and small than max_low_pfn, otherwise will waste some page table entries
- */
-
-#if PTRS_PER_PMD > 1
-#define PAGE_TABLE_SIZE(pages) (((pages) / PTRS_PER_PMD) + PTRS_PER_PGD)
-#else
-#define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD)
-#endif
#define SIZEOF_PTREGS 17*4
/*
- * Number of possible pages in the lowmem region.
- *
- * We shift 2 by 31 instead of 1 by 32 to the left in order to avoid a
- * gas warning about overflowing shift count when gas has been compiled
- * with only a host target support using a 32-bit type for internal
- * representation.
- */
-LOWMEM_PAGES = (((2<<31) - __PAGE_OFFSET) >> PAGE_SHIFT)
-
-/* Enough space to fit pagetables for the low memory linear map */
-MAPPING_BEYOND_END = PAGE_TABLE_SIZE(LOWMEM_PAGES) << PAGE_SHIFT
-
-/*
* Worst-case size of the kernel mapping we need to make:
* a relocatable kernel can live anywhere in lowmem, so we need to be able
* to map all of lowmem.
@@ -160,90 +127,15 @@ ENTRY(startup_32)
call load_ucode_bsp
#endif
-/*
- * Initialize page tables. This creates a PDE and a set of page
- * tables, which are located immediately beyond __brk_base. The variable
- * _brk_end is set up to point to the first "safe" location.
- * Mappings are created both at virtual address 0 (identity mapping)
- * and PAGE_OFFSET for up to _end.
- */
-#ifdef CONFIG_X86_PAE
-
- /*
- * In PAE mode initial_page_table is statically defined to contain
- * enough entries to cover the VMSPLIT option (that is the top 1, 2 or 3
- * entries). The identity mapping is handled by pointing two PGD entries
- * to the first kernel PMD.
- *
- * Note the upper half of each PMD or PTE are always zero at this stage.
- */
-
-#define KPMDS (((-__PAGE_OFFSET) >> 30) & 3) /* Number of kernel PMDs */
-
- xorl %ebx,%ebx /* %ebx is kept at zero */
-
- movl $pa(__brk_base), %edi
- movl $pa(initial_pg_pmd), %edx
- movl $PTE_IDENT_ATTR, %eax
-10:
- leal PDE_IDENT_ATTR(%edi),%ecx /* Create PMD entry */
- movl %ecx,(%edx) /* Store PMD entry */
- /* Upper half already zero */
- addl $8,%edx
- movl $512,%ecx
-11:
- stosl
- xchgl %eax,%ebx
- stosl
- xchgl %eax,%ebx
- addl $0x1000,%eax
- loop 11b
-
- /*
- * End condition: we must map up to the end + MAPPING_BEYOND_END.
- */
- movl $pa(_end) + MAPPING_BEYOND_END + PTE_IDENT_ATTR, %ebp
- cmpl %ebp,%eax
- jb 10b
-1:
- addl $__PAGE_OFFSET, %edi
- movl %edi, pa(_brk_end)
- shrl $12, %eax
- movl %eax, pa(max_pfn_mapped)
+ /* Create early pagetables. */
+ call mk_early_pgtbl_32
/* Do early initialization of the fixmap area */
movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax
+#ifdef CONFIG_X86_PAE
+#define KPMDS (((-__PAGE_OFFSET) >> 30) & 3) /* Number of kernel PMDs */
movl %eax,pa(initial_pg_pmd+0x1000*KPMDS-8)
-#else /* Not PAE */
-
-page_pde_offset = (__PAGE_OFFSET >> 20);
-
- movl $pa(__brk_base), %edi
- movl $pa(initial_page_table), %edx
- movl $PTE_IDENT_ATTR, %eax
-10:
- leal PDE_IDENT_ATTR(%edi),%ecx /* Create PDE entry */
- movl %ecx,(%edx) /* Store identity PDE entry */
- movl %ecx,page_pde_offset(%edx) /* Store kernel PDE entry */
- addl $4,%edx
- movl $1024, %ecx
-11:
- stosl
- addl $0x1000,%eax
- loop 11b
- /*
- * End condition: we must map up to the end + MAPPING_BEYOND_END.
- */
- movl $pa(_end) + MAPPING_BEYOND_END + PTE_IDENT_ATTR, %ebp
- cmpl %ebp,%eax
- jb 10b
- addl $__PAGE_OFFSET, %edi
- movl %edi, pa(_brk_end)
- shrl $12, %eax
- movl %eax, pa(max_pfn_mapped)
-
- /* Do early initialization of the fixmap area */
- movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax
+#else
movl %eax,pa(initial_page_table+0xffc)
#endif
@@ -666,6 +558,7 @@ ENTRY(setup_once_ref)
__PAGE_ALIGNED_BSS
.align PAGE_SIZE
#ifdef CONFIG_X86_PAE
+.globl initial_pg_pmd
initial_pg_pmd:
.fill 1024*KPMDS,4,0
#else