* Matt Fleming <[email protected]> wrote:
> On Tue, 18 Oct, at 07:47:38AM, Alex Thorlton wrote:
> > 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]>
> > Cc: Mike Travis <[email protected]>
> > Cc: Russ Anderson <[email protected]>
> > Cc: Dimitri Sivanich <[email protected]>
> > Cc: Thomas Gleixner <[email protected]>
> > Cc: Ingo Molnar <[email protected]>
> > Cc: "H. Peter Anvin" <[email protected]>
> > Cc: Matt Fleming <[email protected]>
> > Cc: Masahiro Yamada <[email protected]>
> > Cc: [email protected]
> > ---
> > arch/x86/platform/uv/bios_uv.c | 10 +++++++++-
> > 1 file changed, 9 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/platform/uv/bios_uv.c b/arch/x86/platform/uv/bios_uv.c
> > index b4d5e95..12b6e52 100644
> > --- 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, u64 a1, u64 a2,
> > u64 a3, u64 a4, u64 a5)
> > */
> > 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 (!test_bit(EFI_OLD_MEMMAP, &efi.flags))
> > + ret = efi_call_virt_pointer(tab, function, (u64)which, a1, a2,
> > a3, a4, a5);
> > + else
> > + ret = efi_call((void *)__va(tab->function), (u64)which, a1, a2,
> > a3, a4, a5);
> > +
> > return ret;
> > }
> > EXPORT_SYMBOL_GPL(uv_bios_call);
>
> Could you please invert the conditional? I had to read it 3 times to
> make sure it was correct given the comment that precedes it. E.g. this
> is preferable,
>
> if (efi_enabled(EFI_OLD_MEMMAP))
> 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);
Also, does 'which' have to be explicitly type-cast to u64? Doesn't the compiler
DTRT?
Thanks,
Ingo
