be354f4081
This reverts commit 53b87cf088.
It causes odd bootup problems on x86-64. Markus Trippelsdorf gets a
repeatable oops, and I see a non-repeatable oops (or constant stream of
messages that scroll off too quickly to read) that seems to go away with
this commit reverted.
So we don't know exactly what is wrong with the commit, but it's
definitely problematic, and worth reverting sooner rather than later.
Bisected-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: H Peter Anvin <hpa@zytor.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
116 lines
3.1 KiB
C
116 lines
3.1 KiB
C
#include <linux/io.h>
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#include <linux/memblock.h>
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#include <asm/cacheflush.h>
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#include <asm/pgtable.h>
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#include <asm/realmode.h>
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struct real_mode_header *real_mode_header;
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u32 *trampoline_cr4_features;
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void __init setup_real_mode(void)
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{
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phys_addr_t mem;
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u16 real_mode_seg;
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u32 *rel;
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u32 count;
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u32 *ptr;
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u16 *seg;
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int i;
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unsigned char *base;
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struct trampoline_header *trampoline_header;
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size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
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#ifdef CONFIG_X86_64
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u64 *trampoline_pgd;
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u64 efer;
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#endif
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/* Has to be in very low memory so we can execute real-mode AP code. */
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mem = memblock_find_in_range(0, 1<<20, size, PAGE_SIZE);
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if (!mem)
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panic("Cannot allocate trampoline\n");
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base = __va(mem);
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memblock_reserve(mem, size);
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real_mode_header = (struct real_mode_header *) base;
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printk(KERN_DEBUG "Base memory trampoline at [%p] %llx size %zu\n",
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base, (unsigned long long)mem, size);
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memcpy(base, real_mode_blob, size);
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real_mode_seg = __pa(base) >> 4;
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rel = (u32 *) real_mode_relocs;
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/* 16-bit segment relocations. */
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count = rel[0];
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rel = &rel[1];
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for (i = 0; i < count; i++) {
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seg = (u16 *) (base + rel[i]);
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*seg = real_mode_seg;
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}
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/* 32-bit linear relocations. */
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count = rel[i];
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rel = &rel[i + 1];
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for (i = 0; i < count; i++) {
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ptr = (u32 *) (base + rel[i]);
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*ptr += __pa(base);
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}
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/* Must be perfomed *after* relocation. */
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trampoline_header = (struct trampoline_header *)
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__va(real_mode_header->trampoline_header);
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#ifdef CONFIG_X86_32
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trampoline_header->start = __pa(startup_32_smp);
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trampoline_header->gdt_limit = __BOOT_DS + 7;
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trampoline_header->gdt_base = __pa(boot_gdt);
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#else
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/*
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* Some AMD processors will #GP(0) if EFER.LMA is set in WRMSR
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* so we need to mask it out.
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*/
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rdmsrl(MSR_EFER, efer);
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trampoline_header->efer = efer & ~EFER_LMA;
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trampoline_header->start = (u64) secondary_startup_64;
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trampoline_cr4_features = &trampoline_header->cr4;
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*trampoline_cr4_features = read_cr4();
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trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);
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trampoline_pgd[0] = __pa(level3_ident_pgt) + _KERNPG_TABLE;
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trampoline_pgd[511] = __pa(level3_kernel_pgt) + _KERNPG_TABLE;
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#endif
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}
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/*
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* set_real_mode_permissions() gets called very early, to guarantee the
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* availability of low memory. This is before the proper kernel page
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* tables are set up, so we cannot set page permissions in that
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* function. Thus, we use an arch_initcall instead.
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*/
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static int __init set_real_mode_permissions(void)
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{
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unsigned char *base = (unsigned char *) real_mode_header;
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size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
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size_t ro_size =
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PAGE_ALIGN(real_mode_header->ro_end) -
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__pa(base);
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size_t text_size =
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PAGE_ALIGN(real_mode_header->ro_end) -
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real_mode_header->text_start;
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unsigned long text_start =
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(unsigned long) __va(real_mode_header->text_start);
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set_memory_nx((unsigned long) base, size >> PAGE_SHIFT);
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set_memory_ro((unsigned long) base, ro_size >> PAGE_SHIFT);
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set_memory_x((unsigned long) text_start, text_size >> PAGE_SHIFT);
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return 0;
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}
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arch_initcall(set_real_mode_permissions);
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