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SubjectRe: [PATCH v3 2/4] efi: Add tracking for dynamically allocated memmaps
Hi Dan,

Thanks for taking the time to really fix this properly.

Comments/questions below.

On Thu, 2 Jan 2020 at 05:29, Dan Williams <dan.j.williams@intel.com> wrote:
>
> In preparation for fixing efi_memmap_alloc() leaks, add support for
> recording whether the memmap was dynamically allocated from slab,
> memblock, or is the original physical memmap provided by the platform.
>
> Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
> arch/x86/platform/efi/efi.c | 2 +-
> arch/x86/platform/efi/quirks.c | 11 ++++++-----
> drivers/firmware/efi/fake_mem.c | 5 +++--
> drivers/firmware/efi/memmap.c | 16 ++++++++++------
> include/linux/efi.h | 8 ++++++--
> 5 files changed, 26 insertions(+), 16 deletions(-)
>
> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index 38d44f36d5ed..7086afbb84fd 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -333,7 +333,7 @@ static void __init efi_clean_memmap(void)
> u64 size = efi.memmap.nr_map - n_removal;
>
> pr_warn("Removing %d invalid memory map entries.\n", n_removal);
> - efi_memmap_install(efi.memmap.phys_map, size);
> + efi_memmap_install(efi.memmap.phys_map, size, 0);
> }
> }
>
> diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
> index f8f0220b6a66..4a71c790f9c3 100644
> --- a/arch/x86/platform/efi/quirks.c
> +++ b/arch/x86/platform/efi/quirks.c
> @@ -244,6 +244,7 @@ EXPORT_SYMBOL_GPL(efi_query_variable_store);
> void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
> {
> phys_addr_t new_phys, new_size;
> + unsigned long flags = 0;
> struct efi_mem_range mr;
> efi_memory_desc_t md;
> int num_entries;
> @@ -272,8 +273,7 @@ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
> num_entries += efi.memmap.nr_map;
>
> new_size = efi.memmap.desc_size * num_entries;
> -
> - new_phys = efi_memmap_alloc(num_entries);
> + new_phys = efi_memmap_alloc(num_entries, &flags);
> if (!new_phys) {
> pr_err("Could not allocate boot services memmap\n");
> return;
> @@ -288,7 +288,7 @@ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
> efi_memmap_insert(&efi.memmap, new, &mr);
> early_memunmap(new, new_size);
>
> - efi_memmap_install(new_phys, num_entries);
> + efi_memmap_install(new_phys, num_entries, flags);
> e820__range_update(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED);
> e820__update_table(e820_table);
> }
> @@ -408,6 +408,7 @@ static void __init efi_unmap_pages(efi_memory_desc_t *md)
> void __init efi_free_boot_services(void)
> {
> phys_addr_t new_phys, new_size;
> + unsigned long flags = 0;
> efi_memory_desc_t *md;
> int num_entries = 0;
> void *new, *new_md;
> @@ -463,7 +464,7 @@ void __init efi_free_boot_services(void)
> return;
>
> new_size = efi.memmap.desc_size * num_entries;
> - new_phys = efi_memmap_alloc(num_entries);
> + new_phys = efi_memmap_alloc(num_entries, &flags);
> if (!new_phys) {
> pr_err("Failed to allocate new EFI memmap\n");
> return;
> @@ -493,7 +494,7 @@ void __init efi_free_boot_services(void)
>
> memunmap(new);
>
> - if (efi_memmap_install(new_phys, num_entries)) {
> + if (efi_memmap_install(new_phys, num_entries, flags)) {
> pr_err("Could not install new EFI memmap\n");
> return;
> }
> diff --git a/drivers/firmware/efi/fake_mem.c b/drivers/firmware/efi/fake_mem.c
> index bb9fc70d0cfa..7e53e5520548 100644
> --- a/drivers/firmware/efi/fake_mem.c
> +++ b/drivers/firmware/efi/fake_mem.c
> @@ -39,6 +39,7 @@ void __init efi_fake_memmap(void)
> int new_nr_map = efi.memmap.nr_map;
> efi_memory_desc_t *md;
> phys_addr_t new_memmap_phy;
> + unsigned long flags = 0;
> void *new_memmap;
> int i;
>
> @@ -55,7 +56,7 @@ void __init efi_fake_memmap(void)
> }
>
> /* allocate memory for new EFI memmap */
> - new_memmap_phy = efi_memmap_alloc(new_nr_map);
> + new_memmap_phy = efi_memmap_alloc(new_nr_map, &flags);
> if (!new_memmap_phy)
> return;
>
> @@ -73,7 +74,7 @@ void __init efi_fake_memmap(void)
> /* swap into new EFI memmap */
> early_memunmap(new_memmap, efi.memmap.desc_size * new_nr_map);
>
> - efi_memmap_install(new_memmap_phy, new_nr_map);
> + efi_memmap_install(new_memmap_phy, new_nr_map, flags);
>

So it is the caller's responsibility to record the flags returned by
efi_memmap_alloc() and pass them into efi_memmap_install(), right?
Given that we are now passing three pieces of info that need to be in
sync between the two, could we use a dedicated data structure instead,
a reference to which is taken by both?


> /* print new EFI memmap */
> efi_print_memmap();
> diff --git a/drivers/firmware/efi/memmap.c b/drivers/firmware/efi/memmap.c
> index 813674ef9000..2b81ee6858a9 100644
> --- a/drivers/firmware/efi/memmap.c
> +++ b/drivers/firmware/efi/memmap.c
> @@ -32,6 +32,7 @@ static phys_addr_t __init __efi_memmap_alloc_late(unsigned long size)
> /**
> * efi_memmap_alloc - Allocate memory for the EFI memory map
> * @num_entries: Number of entries in the allocated map.
> + * @flags: Late map, memblock alloc, slab alloc flags
> *
> * Depending on whether mm_init() has already been invoked or not,
> * either memblock or "normal" page allocation is used.
> @@ -39,20 +40,23 @@ static phys_addr_t __init __efi_memmap_alloc_late(unsigned long size)
> * Returns the physical address of the allocated memory map on
> * success, zero on failure.
> */
> -phys_addr_t __init efi_memmap_alloc(unsigned int num_entries)
> +phys_addr_t __init efi_memmap_alloc(unsigned int num_entries, unsigned long *flags)
> {
> unsigned long size = num_entries * efi.memmap.desc_size;
>
> - if (slab_is_available())
> + if (slab_is_available()) {
> + *flags |= EFI_MEMMAP_SLAB;
> return __efi_memmap_alloc_late(size);
> + }
>
> + *flags |= EFI_MEMMAP_MEMBLOCK;

This assumes flags has neither bit set, but perhaps we should at least
clear the memblock one if we set the slab one?

> return __efi_memmap_alloc_early(size);
> }
>
> /**
> * __efi_memmap_init - Common code for mapping the EFI memory map
> * @data: EFI memory map data
> - * @flags: Use early or late mapping function?
> + * @flags: Use early or late mapping function, and allocator
> *
> * This function takes care of figuring out which function to use to
> * map the EFI memory map in efi.memmap based on how far into the boot
> @@ -192,10 +196,10 @@ int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size)
> *
> * Returns zero on success, a negative error code on failure.
> */
> -int __init efi_memmap_install(phys_addr_t addr, unsigned int nr_map)
> +int __init efi_memmap_install(phys_addr_t addr, unsigned int nr_map,
> + unsigned long flags)
> {
> struct efi_memory_map_data data;
> - unsigned long flags;
>
> efi_memmap_unmap();
>
> @@ -203,7 +207,7 @@ int __init efi_memmap_install(phys_addr_t addr, unsigned int nr_map)
> data.size = efi.memmap.desc_size * nr_map;
> data.desc_version = efi.memmap.desc_version;
> data.desc_size = efi.memmap.desc_size;
> - flags = efi.memmap.flags & EFI_MEMMAP_LATE;
> + flags |= efi.memmap.flags & EFI_MEMMAP_LATE;
>
> return __efi_memmap_init(&data, flags);
> }
> diff --git a/include/linux/efi.h b/include/linux/efi.h
> index b8e930f5ff77..fa2668a992ae 100644
> --- a/include/linux/efi.h
> +++ b/include/linux/efi.h
> @@ -796,6 +796,8 @@ struct efi_memory_map {
> unsigned long desc_version;
> unsigned long desc_size;
> #define EFI_MEMMAP_LATE (1UL << 0)
> +#define EFI_MEMMAP_MEMBLOCK (1UL << 1)
> +#define EFI_MEMMAP_SLAB (1UL << 2)
> unsigned long flags;
> };
>
> @@ -1057,11 +1059,13 @@ static inline efi_status_t efi_query_variable_store(u32 attributes,
> #endif
> extern void __iomem *efi_lookup_mapped_addr(u64 phys_addr);
>
> -extern phys_addr_t __init efi_memmap_alloc(unsigned int num_entries);
> +extern phys_addr_t __init efi_memmap_alloc(unsigned int num_entries,
> + unsigned long *flags);
> extern int __init efi_memmap_init_early(struct efi_memory_map_data *data);
> extern int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size);
> extern void __init efi_memmap_unmap(void);
> -extern int __init efi_memmap_install(phys_addr_t addr, unsigned int nr_map);
> +extern int __init efi_memmap_install(phys_addr_t addr, unsigned int nr_map,
> + unsigned long flags);
> extern int __init efi_memmap_split_count(efi_memory_desc_t *md,
> struct range *range);
> extern void __init efi_memmap_insert(struct efi_memory_map *old_memmap,
>

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