| Message ID | 20200103113953.9571-20-ardb@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | More EFI updates for v5.6 | expand |
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;
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> --- arch/x86/platform/efi/efi_64.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)