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Date: Wed, 18 Jan 2017 10:16:54 +0800
From: Dave Young <dyoung@...hat.com>
To: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc: Matt Fleming <matt@...eblueprint.co.uk>,
"linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"x86@...nel.org" <x86@...nel.org>,
Nicolai Stange <nicstange@...il.com>,
Ingo Molnar <mingo@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>,
"hpa@...or.com" <hpa@...or.com>,
Dan Williams <dan.j.williams@...el.com>,
Mika Penttilä <mika.penttila@...tfour.com>,
Bhupesh Sharma <bhsharma@...hat.com>
Subject: Re: [PATCH V2 1/4] efi/x86: move efi bgrt init code to early init
code
On 01/17/17 at 05:10pm, Ard Biesheuvel wrote:
> On 16 January 2017 at 02:45, Dave Young <dyoung@...hat.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@...hat.com>
> > ---
> > v1->v2: efi_bgrt_init: check table length first before copying bgrt table
> > error checking in drivers/acpi/bgrt.c
> > arch/x86/kernel/acpi/boot.c | 12 +++++++
> > arch/x86/platform/efi/efi-bgrt.c | 59 ++++++++++++++++-----------------------
> > arch/x86/platform/efi/efi.c | 5 ---
> > drivers/acpi/bgrt.c | 28 +++++++++++++-----
> > include/linux/efi-bgrt.h | 7 +---
> > init/main.c | 1
> > 6 files changed, 60 insertions(+), 52 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
> > +
>
> Please drop the #ifdef / #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
>
> Please replace with
>
> if (IS_ENABLED(CONFIG_ACPI_BGRT))
>
> > + acpi_table_parse("BGRT", acpi_parse_bgrt);
> > +#endif
> >
>
> and perhaps we should add a #define for ACPI_SIG_BGRT as well?
There is ACPI_SIG_BGRT already in acpi header file, will use it and
switch to if (IS_ENABLED..) as you mentioned.
>
> > 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 {
> > @@ -28,66 +27,58 @@ 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;
> > + struct acpi_table_bgrt *bgrt = &bgrt_tab;
> >
> > if (acpi_disabled)
> > return;
> >
> > - status = acpi_get_table("BGRT", 0,
> > - (struct acpi_table_header **)&bgrt_tab);
> > - if (ACPI_FAILURE(status))
> > - return;
> > -
> > - if (bgrt_tab->header.length < sizeof(*bgrt_tab)) {
> > + if (table->length < sizeof(bgrt_tab)) {
> > pr_notice("Ignoring BGRT: invalid length %u (expected %zu)\n",
> > - bgrt_tab->header.length, sizeof(*bgrt_tab));
> > + table->length, sizeof(bgrt_tab));
> > return;
> > }
> > - if (bgrt_tab->version != 1) {
> > + *bgrt = *(struct acpi_table_bgrt *)table;
> > + if (bgrt->version != 1) {
> > pr_notice("Ignoring BGRT: invalid version %u (expected 1)\n",
> > - bgrt_tab->version);
> > - return;
> > + bgrt->version);
> > + goto out;
> > }
> > - if (bgrt_tab->status & 0xfe) {
> > + if (bgrt->status & 0xfe) {
> > pr_notice("Ignoring BGRT: reserved status bits are non-zero %u\n",
> > - bgrt_tab->status);
> > - return;
> > + bgrt->status);
> > + goto out;
> > }
> > - if (bgrt_tab->image_type != 0) {
> > + if (bgrt->image_type != 0) {
> > pr_notice("Ignoring BGRT: invalid image type %u (expected 0)\n",
> > - bgrt_tab->image_type);
> > - return;
> > + bgrt->image_type);
> > + goto out;
> > }
> > - if (!bgrt_tab->image_address) {
> > + if (!bgrt->image_address) {
> > pr_notice("Ignoring BGRT: null image address\n");
> > - return;
> > + goto out;
> > }
> >
> > - image = memremap(bgrt_tab->image_address, sizeof(bmp_header), MEMREMAP_WB);
> > + image = early_memremap(bgrt->image_address, sizeof(bmp_header));
> > if (!image) {
> > pr_notice("Ignoring BGRT: failed to map image header memory\n");
> > - return;
> > + goto out;
> > }
> >
> > 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);
> > - return;
> > + goto out;
> > }
> > bgrt_image_size = bmp_header.size;
> > + efi_mem_reserve(bgrt->image_address, bgrt_image_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);
> > + return;
> > +out:
> > + memset(bgrt, 0, sizeof(bgrt_tab));
> > }
> > --- 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);
> >
> > @@ -84,15 +85,24 @@ 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");
> > + return -ENOMEM;
> > + }
> > +
> > bin_attr_image.private = bgrt_image;
> > bin_attr_image.size = bgrt_image_size;
> >
> > bgrt_kobj = kobject_create_and_add("bgrt", acpi_kobj);
> > - if (!bgrt_kobj)
> > - return -EINVAL;
> > + if (!bgrt_kobj) {
> > + ret = -EINVAL;
> > + goto out_memmap;
> > + }
> >
> > ret = sysfs_create_group(bgrt_kobj, &bgrt_attribute_group);
> > if (ret)
> > @@ -102,6 +112,8 @@ static int __init bgrt_init(void)
> >
> > out_kobject:
> > kobject_put(bgrt_kobj);
> > +out_memmap:
> > + memunmap(bgrt_image);
> > return ret;
> > }
> > device_initcall(bgrt_init);
> > --- linux-x86.orig/include/linux/efi-bgrt.h
> > +++ linux-x86/include/linux/efi-bgrt.h
> > @@ -5,16 +5,15 @@
> >
> > #include <linux/acpi.h>
Will move above including before #ifdef CONFIG_ACPI_BGRT because #else
dummy function declaration use the argument type. Or there will be a
build warning.
> >
> > -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
> > @@ -546,11 +546,6 @@ 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();
> > }
> >
> >
> >
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