]> Git Repo - linux.git/commit
efi/x86: Don't map the entire kernel text RW for mixed mode
authorArd Biesheuvel <[email protected]>
Mon, 13 Jan 2020 17:22:37 +0000 (18:22 +0100)
committerIngo Molnar <[email protected]>
Mon, 20 Jan 2020 07:13:01 +0000 (08:13 +0100)
commitd9e3d2c4f103200d87f2c243a84c1fd3b3bfea8c
tree6cca34c1758374f07c855490b34d9e126f3734b7
parent75fbef0a8b6b4bb19b9a91b5214f846c2dc5139e
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 <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
arch/x86/platform/efi/efi_64.c
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