Re: [PATCH v2 1/2] efi: Iterate over efi.memmap in for_each_efi_memory_desc

From: Ard Biesheuvel
Date: Thu Apr 14 2016 - 09:24:41 EST

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In reply to: Matt Fleming: "[PATCH v2 1/2] efi: Iterate over efi.memmap in for_each_efi_memory_desc"
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On 14 April 2016 at 14:13, Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx> wrote:
> Most of the users of for_each_efi_memory_desc() are equally happy
> iterating over the EFI memory map in efi.memmap instead of 'memmap',
> since the former is usually a pointer to the later.
>

s/later/latter/

> For those users that want to specify an EFI memory map other than
> efi.memmap, that can be done using for_each_efi_memory_desc_in_map().
> One such example is in the libstub code where the firmware is queried
> directly for the memory map, it gets iterated over, and then freed.
>
> This change goes part of the way toward deleting the global 'memmap'
> variable, which is not universally available on all architectures
> (notably ia64) and is rather poorly named.
>
> Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> Cc: Mark Salter <msalter@xxxxxxxxxx>
> Cc: Leif Lindholm <leif.lindholm@xxxxxxxxxx>
> Signed-off-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
> ---
> Change in v2:
> - Fix bisection breakage due to efi->memmap misuse
>

Reviewed-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>

> arch/x86/platform/efi/efi.c | 43 ++++++++------------------
> arch/x86/platform/efi/efi_64.c | 10 ++----
> arch/x86/platform/efi/quirks.c | 10 +++---
> drivers/firmware/efi/arm-init.c | 4 +--
> drivers/firmware/efi/arm-runtime.c | 2 +-
> drivers/firmware/efi/efi.c | 6 +---
> drivers/firmware/efi/fake_mem.c | 3 +-
> drivers/firmware/efi/libstub/efi-stub-helper.c | 6 ++--
> include/linux/efi.h | 11 ++++++-
> 9 files changed, 39 insertions(+), 56 deletions(-)
>
> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index df393eab0e50..6f499819a27f 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -119,11 +119,10 @@ void efi_get_time(struct timespec *now)
>
> void __init efi_find_mirror(void)
> {
> - void *p;
> + efi_memory_desc_t *md;
> u64 mirror_size = 0, total_size = 0;
>
> - for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
> - efi_memory_desc_t *md = p;
> + for_each_efi_memory_desc(md) {
> unsigned long long start = md->phys_addr;
> unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
>
> @@ -146,10 +145,9 @@ void __init efi_find_mirror(void)
>
> static void __init do_add_efi_memmap(void)
> {
> - void *p;
> + efi_memory_desc_t *md;
>
> - for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
> - efi_memory_desc_t *md = p;
> + for_each_efi_memory_desc(md) {
> unsigned long long start = md->phys_addr;
> unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
> int e820_type;
> @@ -226,17 +224,13 @@ void __init efi_print_memmap(void)
> {
> #ifdef EFI_DEBUG
> efi_memory_desc_t *md;
> - void *p;
> - int i;
> + int i = 0;
>
> - for (p = memmap.map, i = 0;
> - p < memmap.map_end;
> - p += memmap.desc_size, i++) {
> + for_each_efi_memory_desc(md) {
> char buf[64];
>
> - md = p;
> pr_info("mem%02u: %s range=[0x%016llx-0x%016llx] (%lluMB)\n",
> - i, efi_md_typeattr_format(buf, sizeof(buf), md),
> + i++, efi_md_typeattr_format(buf, sizeof(buf), md),
> md->phys_addr,
> md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1,
> (md->num_pages >> (20 - EFI_PAGE_SHIFT)));
> @@ -550,12 +544,9 @@ void __init efi_set_executable(efi_memory_desc_t *md, bool executable)
> void __init runtime_code_page_mkexec(void)
> {
> efi_memory_desc_t *md;
> - void *p;
>
> /* Make EFI runtime service code area executable */
> - for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
> - md = p;
> -
> + for_each_efi_memory_desc(md) {
> if (md->type != EFI_RUNTIME_SERVICES_CODE)
> continue;
>
> @@ -602,12 +593,10 @@ void __init old_map_region(efi_memory_desc_t *md)
> /* Merge contiguous regions of the same type and attribute */
> static void __init efi_merge_regions(void)
> {
> - void *p;
> efi_memory_desc_t *md, *prev_md = NULL;
>
> - for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
> + for_each_efi_memory_desc(md) {
> u64 prev_size;
> - md = p;
>
> if (!prev_md) {
> prev_md = md;
> @@ -650,15 +639,13 @@ static void __init save_runtime_map(void)
> {
> #ifdef CONFIG_KEXEC_CORE
> efi_memory_desc_t *md;
> - void *tmp, *p, *q = NULL;
> + void *tmp, *q = NULL;
> int count = 0;
>
> if (efi_enabled(EFI_OLD_MEMMAP))
> return;
>
> - for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
> - md = p;
> -
> + for_each_efi_memory_desc(md) {
> if (!(md->attribute & EFI_MEMORY_RUNTIME) ||
> (md->type == EFI_BOOT_SERVICES_CODE) ||
> (md->type == EFI_BOOT_SERVICES_DATA))
> @@ -814,7 +801,6 @@ static void __init kexec_enter_virtual_mode(void)
> #ifdef CONFIG_KEXEC_CORE
> efi_memory_desc_t *md;
> unsigned int num_pages;
> - void *p;
>
> efi.systab = NULL;
>
> @@ -838,8 +824,7 @@ static void __init kexec_enter_virtual_mode(void)
> * Map efi regions which were passed via setup_data. The virt_addr is a
> * fixed addr which was used in first kernel of a kexec boot.
> */
> - for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
> - md = p;
> + for_each_efi_memory_desc(md) {
> efi_map_region_fixed(md); /* FIXME: add error handling */
> get_systab_virt_addr(md);
> }
> @@ -1009,13 +994,11 @@ void __init efi_enter_virtual_mode(void)
> u32 efi_mem_type(unsigned long phys_addr)
> {
> efi_memory_desc_t *md;
> - void *p;
>
> if (!efi_enabled(EFI_MEMMAP))
> return 0;
>
> - for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
> - md = p;
> + for_each_efi_memory_desc(md) {
> if ((md->phys_addr <= phys_addr) &&
> (phys_addr < (md->phys_addr +
> (md->num_pages << EFI_PAGE_SHIFT))))
> diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
> index 49e4dd4a1f58..6e7242be1c87 100644
> --- a/arch/x86/platform/efi/efi_64.c
> +++ b/arch/x86/platform/efi/efi_64.c
> @@ -55,14 +55,12 @@ struct efi_scratch efi_scratch;
> static void __init early_code_mapping_set_exec(int executable)
> {
> efi_memory_desc_t *md;
> - void *p;
>
> if (!(__supported_pte_mask & _PAGE_NX))
> return;
>
> /* Make EFI service code area executable */
> - for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
> - md = p;
> + for_each_efi_memory_desc(md) {
> if (md->type == EFI_RUNTIME_SERVICES_CODE ||
> md->type == EFI_BOOT_SERVICES_CODE)
> efi_set_executable(md, executable);
> @@ -253,7 +251,7 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
> * Map all of RAM so that we can access arguments in the 1:1
> * mapping when making EFI runtime calls.
> */
> - for_each_efi_memory_desc(&memmap, md) {
> + for_each_efi_memory_desc(md) {
> if (md->type != EFI_CONVENTIONAL_MEMORY &&
> md->type != EFI_LOADER_DATA &&
> md->type != EFI_LOADER_CODE)
> @@ -398,7 +396,6 @@ void __init efi_runtime_update_mappings(void)
> unsigned long pfn;
> pgd_t *pgd = efi_pgd;
> efi_memory_desc_t *md;
> - void *p;
>
> if (efi_enabled(EFI_OLD_MEMMAP)) {
> if (__supported_pte_mask & _PAGE_NX)
> @@ -409,9 +406,8 @@ void __init efi_runtime_update_mappings(void)
> if (!efi_enabled(EFI_NX_PE_DATA))
> return;
>
> - for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
> + for_each_efi_memory_desc(md) {
> unsigned long pf = 0;
> - md = p;
>
> if (!(md->attribute & EFI_MEMORY_RUNTIME))
> continue;
> diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
> index ab50ada1d56e..097cb09d917b 100644
> --- a/arch/x86/platform/efi/quirks.c
> +++ b/arch/x86/platform/efi/quirks.c
> @@ -195,10 +195,9 @@ static bool can_free_region(u64 start, u64 size)
> */
> void __init efi_reserve_boot_services(void)
> {
> - void *p;
> + efi_memory_desc_t *md;
>
> - for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
> - efi_memory_desc_t *md = p;
> + for_each_efi_memory_desc(md) {
> u64 start = md->phys_addr;
> u64 size = md->num_pages << EFI_PAGE_SHIFT;
> bool already_reserved;
> @@ -250,10 +249,9 @@ void __init efi_reserve_boot_services(void)
>
> void __init efi_free_boot_services(void)
> {
> - void *p;
> + efi_memory_desc_t *md;
>
> - for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
> - efi_memory_desc_t *md = p;
> + for_each_efi_memory_desc(md) {
> unsigned long long start = md->phys_addr;
> unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
>
> diff --git a/drivers/firmware/efi/arm-init.c b/drivers/firmware/efi/arm-init.c
> index 64f0e90c9f60..96e7fe548164 100644
> --- a/drivers/firmware/efi/arm-init.c
> +++ b/drivers/firmware/efi/arm-init.c
> @@ -40,7 +40,7 @@ static phys_addr_t efi_to_phys(unsigned long addr)
> {
> efi_memory_desc_t *md;
>
> - for_each_efi_memory_desc(&memmap, md) {
> + for_each_efi_memory_desc_in_map(&memmap, md) {
> if (!(md->attribute & EFI_MEMORY_RUNTIME))
> continue;
> if (md->virt_addr == 0)
> @@ -145,7 +145,7 @@ static __init void reserve_regions(void)
> if (efi_enabled(EFI_DBG))
> pr_info("Processing EFI memory map:\n");
>
> - for_each_efi_memory_desc(&memmap, md) {
> + for_each_efi_memory_desc_in_map(&memmap, md) {
> paddr = md->phys_addr;
> npages = md->num_pages;
>
> diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c
> index 771750df6b7d..1cfbfaf57a2d 100644
> --- a/drivers/firmware/efi/arm-runtime.c
> +++ b/drivers/firmware/efi/arm-runtime.c
> @@ -48,7 +48,7 @@ static bool __init efi_virtmap_init(void)
> init_new_context(NULL, &efi_mm);
>
> systab_found = false;
> - for_each_efi_memory_desc(&memmap, md) {
> + for_each_efi_memory_desc(md) {
> phys_addr_t phys = md->phys_addr;
> int ret;
>
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 3a69ed5ecfcb..4b533ce73374 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -620,16 +620,12 @@ char * __init efi_md_typeattr_format(char *buf, size_t size,
> */
> u64 __weak efi_mem_attributes(unsigned long phys_addr)
> {
> - struct efi_memory_map *map;
> efi_memory_desc_t *md;
> - void *p;
>
> if (!efi_enabled(EFI_MEMMAP))
> return 0;
>
> - map = efi.memmap;
> - for (p = map->map; p < map->map_end; p += map->desc_size) {
> - md = p;
> + for_each_efi_memory_desc(md) {
> if ((md->phys_addr <= phys_addr) &&
> (phys_addr < (md->phys_addr +
> (md->num_pages << EFI_PAGE_SHIFT))))
> diff --git a/drivers/firmware/efi/fake_mem.c b/drivers/firmware/efi/fake_mem.c
> index ed3a854950cc..f55b75b2e1f4 100644
> --- a/drivers/firmware/efi/fake_mem.c
> +++ b/drivers/firmware/efi/fake_mem.c
> @@ -68,8 +68,7 @@ void __init efi_fake_memmap(void)
> return;
>
> /* count up the number of EFI memory descriptor */
> - for (old = memmap.map; old < memmap.map_end; old += memmap.desc_size) {
> - md = old;
> + for_each_efi_memory_desc(md) {
> start = md->phys_addr;
> end = start + (md->num_pages << EFI_PAGE_SHIFT) - 1;
>
> diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
> index 29ed2f9b218c..3bd127f95315 100644
> --- a/drivers/firmware/efi/libstub/efi-stub-helper.c
> +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
> @@ -125,10 +125,12 @@ unsigned long get_dram_base(efi_system_table_t *sys_table_arg)
>
> map.map_end = map.map + map_size;
>
> - for_each_efi_memory_desc(&map, md)
> - if (md->attribute & EFI_MEMORY_WB)
> + for_each_efi_memory_desc_in_map(&map, md) {
> + if (md->attribute & EFI_MEMORY_WB) {
> if (membase > md->phys_addr)
> membase = md->phys_addr;
> + }
> + }
>
> efi_call_early(free_pool, map.map);
>
> diff --git a/include/linux/efi.h b/include/linux/efi.h
> index 1545098b0565..17ef4471e603 100644
> --- a/include/linux/efi.h
> +++ b/include/linux/efi.h
> @@ -958,11 +958,20 @@ static inline void efi_fake_memmap(void) { }
> #endif
>
> /* Iterate through an efi_memory_map */
> -#define for_each_efi_memory_desc(m, md) \
> +#define for_each_efi_memory_desc_in_map(m, md) \
> for ((md) = (m)->map; \
> (md) <= (efi_memory_desc_t *)((m)->map_end - (m)->desc_size); \
> (md) = (void *)(md) + (m)->desc_size)
>
> +/**
> + * for_each_efi_memory_desc - iterate over descriptors in efi.memmap
> + * @md: the efi_memory_desc_t * iterator
> + *
> + * Once the loop finishes @md must not be accessed.
> + */
> +#define for_each_efi_memory_desc(md) \
> + for_each_efi_memory_desc_in_map(efi.memmap, md)
> +
> /*
> * Format an EFI memory descriptor's type and attributes to a user-provided
> * character buffer, as per snprintf(), and return the buffer.
> --
> 2.7.3
>

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In reply to: Matt Fleming: "[PATCH v2 1/2] efi: Iterate over efi.memmap in for_each_efi_memory_desc"
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