On Sun, 06 Nov, at 02:02:54PM, Borislav Petkov wrote: > Hi Matt, > > please doublecheck me on this but I think we're fine using an unsigned > long. > > Thanks. > > --- > From: Borislav Petkov <b...@suse.de> > Date: Sun, 6 Nov 2016 13:49:10 +0100 > Subject: [PATCH] x86/efi: Fix EFI memmap pointer size warning > MIME-Version: 1.0 > Content-Type: text/plain; charset=UTF-8 > Content-Transfer-Encoding: 8bit > > Fix this when building on 32-bit: > > arch/x86/platform/efi/efi.c: In function ‘__efi_enter_virtual_mode’: > arch/x86/platform/efi/efi.c:911:5: warning: cast to pointer from integer of > different size [-Wint-to-pointer-cast] > (efi_memory_desc_t *)pa); > ^ > arch/x86/platform/efi/efi.c:918:5: warning: cast to pointer from integer of > different size [-Wint-to-pointer-cast] > (efi_memory_desc_t *)pa); > ^ > > The @pa local variable is declared as phys_addr_t and that is a u64 when > CONFIG_PHYS_ADDR_T_64BIT=y. (The last is enabled on 32-bit on a PAE > build.) > > However, its value comes from __pa() which is basically doing pointer > arithmetic and checking, and returns unsigned long as it is the native > pointer width. > > So let's use an unsigned long too. It should be fine to do so because > the later users cast it to a pointer too. > > Signed-off-by: Borislav Petkov <b...@suse.de> > Cc: Matt Fleming <m...@codeblueprint.co.uk> > --- > arch/x86/platform/efi/efi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c > index bf99aa7005eb..936a488d6cf6 100644 > --- a/arch/x86/platform/efi/efi.c > +++ b/arch/x86/platform/efi/efi.c > @@ -861,7 +861,7 @@ static void __init __efi_enter_virtual_mode(void) > int count = 0, pg_shift = 0; > void *new_memmap = NULL; > efi_status_t status; > - phys_addr_t pa; > + unsigned long pa; > > efi.systab = NULL; >
Right, this does look correct given that __pa() uses 'unsigned long'. I think the reason this is safe on PAE is that __get_free_pages() is guaranteed to return a 32-bit address, and will not return HIGHMEM pages. Which makes __pa() legal and 'unsigned long' the correct type. Want me to take this through the EFI tree?
