diff options
| author | Ard Biesheuvel <ardb@kernel.org> | 2020-01-13 18:22:37 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-01-20 08:13:01 +0100 |
| commit | d9e3d2c4f103200d87f2c243a84c1fd3b3bfea8c (patch) | |
| tree | 6cca34c1758374f07c855490b34d9e126f3734b7 /arch/x86/platform | |
| parent | 75fbef0a8b6b4bb19b9a91b5214f846c2dc5139e (diff) | |
efi/x86: Don't map the entire kernel text RW for mixed mode
The mixed mode thunking routine requires a part of it to be
mapped 1:1, and for this reason, we currently map the entire
kernel .text read/write in the EFI page tables, which is bad.
In fact, the kernel_map_pages_in_pgd() invocation that installs
this mapping is entirely redundant, since all of DRAM is already
1:1 mapped read/write in the EFI page tables when we reach this
point, which means that .rodata is mapped read-write as well.
So let's remap both .text and .rodata read-only in the EFI
page tables.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200113172245.27925-6-ardb@kernel.org
Diffstat (limited to 'arch/x86/platform')
| -rw-r--r-- | arch/x86/platform/efi/efi_64.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index c13fa2150976..6ec58ff60b56 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -391,11 +391,11 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) efi_scratch.phys_stack = page_to_phys(page + 1); /* stack grows down */ - npages = (_etext - _text) >> PAGE_SHIFT; + npages = (__end_rodata_aligned - _text) >> PAGE_SHIFT; text = __pa(_text); pfn = text >> PAGE_SHIFT; - pf = _PAGE_RW | _PAGE_ENC; + pf = _PAGE_ENC; if (kernel_map_pages_in_pgd(pgd, pfn, text, npages, pf)) { pr_err("Failed to map kernel text 1:1\n"); return 1; |