On 08/16/17 at 12:37pm, Matt Fleming wrote: > On Mon, 14 Aug, at 10:54:23PM, Baoquan He wrote: > > The existing map iteration helper for_each_efi_memory_desc_in_map can > > only be used after OS initializes EFI to fill data of struct efi_memory_map. > > Should this say "EFI subsystem"? The firmware doesn't care about the > kernel's internal data structures.
Sounds reasonable. Let me update and maybe repost to this thread directly. Thanks! > > > Before that we also need iterate map descriptors which are stored in several > > intermediate structures, like struct efi_boot_memmap for arch independent > > usage and struct efi_info for x86 arch only. > > > > Introduce efi_early_memdesc_ptr to get pointer to a map descriptor, and > > replace several places of open code with it. > > > > Suggested-by: Ingo Molnar <mi...@kernel.org> > > Signed-off-by: Baoquan He <b...@redhat.com> > > --- > > arch/x86/boot/compressed/eboot.c | 2 +- > > drivers/firmware/efi/libstub/efi-stub-helper.c | 4 ++-- > > include/linux/efi.h | 21 +++++++++++++++++++++ > > 3 files changed, 24 insertions(+), 3 deletions(-) > > > > diff --git a/arch/x86/boot/compressed/eboot.c > > b/arch/x86/boot/compressed/eboot.c > > index c3e869eaef0c..e007887a33b0 100644 > > --- a/arch/x86/boot/compressed/eboot.c > > +++ b/arch/x86/boot/compressed/eboot.c > > @@ -767,7 +767,7 @@ static efi_status_t setup_e820(struct boot_params > > *params, > > m |= (u64)efi->efi_memmap_hi << 32; > > #endif > > > > - d = (efi_memory_desc_t *)(m + (i * efi->efi_memdesc_size)); > > + d = efi_early_memdesc_ptr(m, efi->efi_memdesc_size, i); > > switch (d->type) { > > case EFI_RESERVED_TYPE: > > case EFI_RUNTIME_SERVICES_CODE: > > diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c > > b/drivers/firmware/efi/libstub/efi-stub-helper.c > > index b0184360efc6..50a9cab5a834 100644 > > --- a/drivers/firmware/efi/libstub/efi-stub-helper.c > > +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c > > @@ -205,7 +205,7 @@ efi_status_t efi_high_alloc(efi_system_table_t > > *sys_table_arg, > > unsigned long m = (unsigned long)map; > > u64 start, end; > > > > - desc = (efi_memory_desc_t *)(m + (i * desc_size)); > > + desc = efi_early_memdesc_ptr(m, desc_size, i); > > if (desc->type != EFI_CONVENTIONAL_MEMORY) > > continue; > > > > @@ -298,7 +298,7 @@ efi_status_t efi_low_alloc(efi_system_table_t > > *sys_table_arg, > > unsigned long m = (unsigned long)map; > > u64 start, end; > > > > - desc = (efi_memory_desc_t *)(m + (i * desc_size)); > > + desc = efi_early_memdesc_ptr(m, desc_size, i); > > > > if (desc->type != EFI_CONVENTIONAL_MEMORY) > > continue; > > diff --git a/include/linux/efi.h b/include/linux/efi.h > > index 8269bcb8ccf7..9783d9e4a4b2 100644 > > --- a/include/linux/efi.h > > +++ b/include/linux/efi.h > > @@ -1020,6 +1020,27 @@ extern int efi_memattr_init(void); > > extern int efi_memattr_apply_permissions(struct mm_struct *mm, > > efi_memattr_perm_setter fn); > > > > +/* > > + * efi_early_memdesc_ptr - get the n-th efi memmap descriptor > > + * @map: the start of efi memmap > > + * @desc_size: the size of space for each efi memmap descriptor > > + * @n: the index of efi memmap descriptor > > + * > > + * EFI boot service provides function GetMemoryMap() to get a copy of the > > + * current memory map which is an array of memory descriptors, each of > > + * which describes a contiguous block of memory. And also get the size of > > + * map, and the size of each descriptor, etc. Note that per section 6.2 of > > + * UEFI Spec 2.6 Errata A, the returned size of each descriptor might not > > + * be equal to sizeof(efi_memory_memdesc_t) since efi_memory_memdesc_t may > > + * be extended in the future in response to hardware innovation. Thus OS > > + * MUST use the returned size of descriptor to find the start of each > > + * efi_memory_memdesc_t in the memory map array. This should only be used > > + * during bootup since for_each_efi_memory_desc_xxx is suggested after OS > > + * initializes EFI to fill data of struct efi_memory_map. > > + */ > > Again, please use "EFI subsystem" here. Sure, will do. > > > +#define efi_early_memdesc_ptr(map, desc_size, n) \ > > + (efi_memory_desc_t *)((void *)(map) + ((n) * (desc_size))) > > + > > /* Iterate through an efi_memory_map */ > > #define for_each_efi_memory_desc_in_map(m, md) > > \ > > for ((md) = (m)->map; \ > > Otherwise, this looks OK to me. Thanks for reviewing!