4.8-stable review patch. If anyone has any objections, please let me know.
------------------ From: Alex Thorlton <[email protected]> commit caef78b6cdeddf4ad364f95910bba6b43b8eb9bf upstream. Some time ago, we brought our UV BIOS callback code up to speed with the new EFI memory mapping scheme, in commit: d1be84a232e3 ("x86/uv: Update uv_bios_call() to use efi_call_virt_pointer()") By leveraging some changes that I made to a few of the EFI runtime callback mechanisms, in commit: 80e75596079f ("efi: Convert efi_call_virt() to efi_call_virt_pointer()") This got everything running smoothly on UV, with the new EFI mapping code. However, this left one, small loose end, in that EFI_OLD_MEMMAP (a.k.a. efi=old_map) will no longer work on UV, on kernels that include the aforementioned changes. At the time this was not a major issue (in fact, it still really isn't), but there's no reason that EFI_OLD_MEMMAP *shouldn't* work on our systems. This commit adds a check into uv_bios_call(), to see if we have the EFI_OLD_MEMMAP bit set in efi.flags. If it is set, we fall back to using our old callback method, which uses efi_call() directly on the __va() of our function pointer. Signed-off-by: Alex Thorlton <[email protected]> Acked-by: Matt Fleming <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Ard Biesheuvel <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: Dimitri Sivanich <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Masahiro Yamada <[email protected]> Cc: Mike Travis <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Russ Anderson <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/platform/uv/bios_uv.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) --- a/arch/x86/platform/uv/bios_uv.c +++ b/arch/x86/platform/uv/bios_uv.c @@ -40,7 +40,15 @@ s64 uv_bios_call(enum uv_bios_cmd which, */ return BIOS_STATUS_UNIMPLEMENTED; - ret = efi_call_virt_pointer(tab, function, (u64)which, a1, a2, a3, a4, a5); + /* + * If EFI_OLD_MEMMAP is set, we need to fall back to using our old EFI + * callback method, which uses efi_call() directly, with the kernel page tables: + */ + if (unlikely(test_bit(EFI_OLD_MEMMAP, &efi.flags))) + ret = efi_call((void *)__va(tab->function), (u64)which, a1, a2, a3, a4, a5); + else + ret = efi_call_virt_pointer(tab, function, (u64)which, a1, a2, a3, a4, a5); + return ret; } EXPORT_SYMBOL_GPL(uv_bios_call);
