Re: [PATCH 2/4] efi/x86: move efi bgrt init code to early init code

Ard Biesheuvel
2017-01-12T16:20:47Z

On 12 January 2017 at 09:41, Dave Young <dyoung@redhat.com> wrote:
> Before invoking the arch specific handler, efi_mem_reserve() reserves
> the given memory region through memblock.
>
> efi_bgrt_init will call efi_mem_reserve after mm_init(), at that time
> memblock is dead and it should not be used any more.
>
> efi bgrt code depend on acpi intialization to get the bgrt acpi table,
> moving bgrt parsing to acpi early boot code can make sure efi_mem_reserve
> in efi bgrt code still use memblock safely.
>
> Signed-off-by: Dave Young <dyoung@redhat.com>

I know this is probably out of scope for you, but since we're moving
things around, any chance we could do so in a manner that will enable
BGRT support for arm64/ACPI? Happy to test/collaborate on this.

> ---
> arch/x86/kernel/acpi/boot.c | 12 +++++++++++
> arch/x86/platform/efi/efi-bgrt.c | 42 +++++++++++++--------------------------
> arch/x86/platform/efi/efi.c | 5 ----
> drivers/acpi/bgrt.c | 21 +++++++++++++------
> include/linux/efi-bgrt.h | 7 ++----
> init/main.c | 1
> 6 files changed, 45 insertions(+), 43 deletions(-)
>
> --- linux-x86.orig/arch/x86/kernel/acpi/boot.c
> +++ linux-x86/arch/x86/kernel/acpi/boot.c
> @@ -35,6 +35,7 @@
> #include <linux/bootmem.h>
> #include <linux/ioport.h>
> #include <linux/pci.h>
> +#include <linux/efi-bgrt.h>
>
> #include <asm/irqdomain.h>
> #include <asm/pci_x86.h>
> @@ -1557,6 +1558,14 @@ int __init early_acpi_boot_init(void)
> return 0;
> }
>
> +#ifdef CONFIG_ACPI_BGRT
> +static int __init acpi_parse_bgrt(struct acpi_table_header *table)
> +{
> + efi_bgrt_init(table);
> + return 0;
> +}
> +#endif
> +
> int __init acpi_boot_init(void)
> {
> /* those are executed after early-quirks are executed */
> @@ -1581,6 +1590,9 @@ int __init acpi_boot_init(void)
> acpi_process_madt();
>
> acpi_table_parse(ACPI_SIG_HPET, acpi_parse_hpet);
> +#ifdef CONFIG_ACPI_BGRT
> + acpi_table_parse("BGRT", acpi_parse_bgrt);
> +#endif
>
> if (!acpi_noirq)
> x86_init.pci.init = pci_acpi_init;
> --- linux-x86.orig/arch/x86/platform/efi/efi-bgrt.c
> +++ linux-x86/arch/x86/platform/efi/efi-bgrt.c
> @@ -19,8 +19,7 @@
> #include <linux/efi.h>
> #include <linux/efi-bgrt.h>
>
> -struct acpi_table_bgrt *bgrt_tab;
> -void *__initdata bgrt_image;
> +struct acpi_table_bgrt bgrt_tab;
> size_t __initdata bgrt_image_size;
>
> struct bmp_header {
> @@ -28,53 +27,49 @@ struct bmp_header {
> u32 size;
> } __packed;
>
> -void __init efi_bgrt_init(void)
> +void __init efi_bgrt_init(struct acpi_table_header *table)
> {
> - acpi_status status;
> void *image;
> struct bmp_header bmp_header;
>
> if (acpi_disabled)
> return;
>
> - status = acpi_get_table("BGRT", 0,
> - (struct acpi_table_header **)&bgrt_tab);
> - if (ACPI_FAILURE(status))
> - return;
> + bgrt_tab = *(struct acpi_table_bgrt *)table;
>
> - if (bgrt_tab->header.length < sizeof(*bgrt_tab)) {
> + if (bgrt_tab.header.length < sizeof(bgrt_tab)) {
> pr_notice("Ignoring BGRT: invalid length %u (expected %zu)\n",
> - bgrt_tab->header.length, sizeof(*bgrt_tab));
> + bgrt_tab.header.length, sizeof(bgrt_tab));
> return;
> }
> - if (bgrt_tab->version != 1) {
> + if (bgrt_tab.version != 1) {
> pr_notice("Ignoring BGRT: invalid version %u (expected 1)\n",
> - bgrt_tab->version);
> + bgrt_tab.version);
> return;
> }
> - if (bgrt_tab->status & 0xfe) {
> + if (bgrt_tab.status & 0xfe) {
> pr_notice("Ignoring BGRT: reserved status bits are non-zero %u\n",
> - bgrt_tab->status);
> + bgrt_tab.status);
> return;
> }
> - if (bgrt_tab->image_type != 0) {
> + if (bgrt_tab.image_type != 0) {
> pr_notice("Ignoring BGRT: invalid image type %u (expected 0)\n",
> - bgrt_tab->image_type);
> + bgrt_tab.image_type);
> return;
> }
> - if (!bgrt_tab->image_address) {
> + if (!bgrt_tab.image_address) {
> pr_notice("Ignoring BGRT: null image address\n");
> return;
> }
>
> - image = memremap(bgrt_tab->image_address, sizeof(bmp_header), MEMREMAP_WB);
> + image = early_memremap(bgrt_tab.image_address, sizeof(bmp_header));
> if (!image) {
> pr_notice("Ignoring BGRT: failed to map image header memory\n");
> return;
> }
>
> memcpy(&bmp_header, image, sizeof(bmp_header));
> - memunmap(image);
> + early_memunmap(image, sizeof(bmp_header));
> if (bmp_header.id != 0x4d42) {
> pr_notice("Ignoring BGRT: Incorrect BMP magic number 0x%x (expected 0x4d42)\n",
> bmp_header.id);
> @@ -82,12 +77,5 @@ void __init efi_bgrt_init(void)
> }
> bgrt_image_size = bmp_header.size;
>
> - bgrt_image = memremap(bgrt_tab->image_address, bmp_header.size, MEMREMAP_WB);
> - if (!bgrt_image) {
> - pr_notice("Ignoring BGRT: failed to map image memory\n");
> - bgrt_image = NULL;
> - return;
> - }
> -
> - efi_mem_reserve(bgrt_tab->image_address, bgrt_image_size);
> + efi_mem_reserve(bgrt_tab.image_address, bgrt_image_size);
> }
> --- linux-x86.orig/drivers/acpi/bgrt.c
> +++ linux-x86/drivers/acpi/bgrt.c
> @@ -15,40 +15,41 @@
> #include <linux/sysfs.h>
> #include <linux/efi-bgrt.h>
>
> +static void *bgrt_image;
> static struct kobject *bgrt_kobj;
>
> static ssize_t show_version(struct device *dev,
> struct device_attribute *attr, char *buf)
> {
> - return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->version);
> + return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.version);
> }
> static DEVICE_ATTR(version, S_IRUGO, show_version, NULL);
>
> static ssize_t show_status(struct device *dev,
> struct device_attribute *attr, char *buf)
> {
> - return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->status);
> + return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.status);
> }
> static DEVICE_ATTR(status, S_IRUGO, show_status, NULL);
>
> static ssize_t show_type(struct device *dev,
> struct device_attribute *attr, char *buf)
> {
> - return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->image_type);
> + return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_type);
> }
> static DEVICE_ATTR(type, S_IRUGO, show_type, NULL);
>
> static ssize_t show_xoffset(struct device *dev,
> struct device_attribute *attr, char *buf)
> {
> - return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->image_offset_x);
> + return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_offset_x);
> }
> static DEVICE_ATTR(xoffset, S_IRUGO, show_xoffset, NULL);
>
> static ssize_t show_yoffset(struct device *dev,
> struct device_attribute *attr, char *buf)
> {
> - return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->image_offset_y);
> + return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_offset_y);
> }
> static DEVICE_ATTR(yoffset, S_IRUGO, show_yoffset, NULL);
>
> @@ -84,9 +85,17 @@ static int __init bgrt_init(void)
> {
> int ret;
>
> - if (!bgrt_image)
> + if (!bgrt_tab.image_address)
> return -ENODEV;
>
> + bgrt_image = memremap(bgrt_tab.image_address, bgrt_image_size,
> + MEMREMAP_WB);
> + if (!bgrt_image) {
> + pr_notice("Ignoring BGRT: failed to map image memory\n");
> + bgrt_image = NULL;
> + return -ENOMEM;
> + }
> +
> bin_attr_image.private = bgrt_image;
> bin_attr_image.size = bgrt_image_size;
>
> --- linux-x86.orig/include/linux/efi-bgrt.h
> +++ linux-x86/include/linux/efi-bgrt.h
> @@ -5,16 +5,15 @@
>
> #include <linux/acpi.h>
>
> -void efi_bgrt_init(void);
> +void efi_bgrt_init(struct acpi_table_header *table);
>
> /* The BGRT data itself; only valid if bgrt_image != NULL. */
> -extern void *bgrt_image;
> extern size_t bgrt_image_size;
> -extern struct acpi_table_bgrt *bgrt_tab;
> +extern struct acpi_table_bgrt bgrt_tab;
>
> #else /* !CONFIG_ACPI_BGRT */
>
> -static inline void efi_bgrt_init(void) {}
> +static inline void efi_bgrt_init(struct acpi_table_header *table) {}
>
> #endif /* !CONFIG_ACPI_BGRT */
>
> --- linux-x86.orig/arch/x86/platform/efi/efi.c
> +++ linux-x86/arch/x86/platform/efi/efi.c
> @@ -476,11 +476,6 @@ void __init efi_init(void)
> efi_print_memmap();
> }
>
> -void __init efi_late_init(void)
> -{
> - efi_bgrt_init();
> -}
> -
> void __init efi_set_executable(efi_memory_desc_t *md, bool executable)
> {
> u64 addr, npages;
> --- linux-x86.orig/init/main.c
> +++ linux-x86/init/main.c
> @@ -663,7 +663,6 @@ asmlinkage __visible void __init start_k
> sfi_init_late();
>
> if (efi_enabled(EFI_RUNTIME_SERVICES)) {
> - efi_late_init();
> efi_free_boot_services();
> }
>
>
>