From 357d291ce035d1b757568058f3c9898c60d125b1 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Wed, 10 Oct 2018 08:14:54 +0200 Subject: x86/xen: Fix boot loader version reported for PVH guests The boot loader version reported via sysfs is wrong in case of the kernel being booted via the Xen PVH boot entry. it should be 2.12 (0x020c), but it is reported to be 2.18 (0x0212). As the current way to set the version is error prone use the more readable variant (2 << 8) | 12. Signed-off-by: Juergen Gross Cc: # 4.12 Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: boris.ostrovsky@oracle.com Cc: bp@alien8.de Cc: corbet@lwn.net Cc: linux-doc@vger.kernel.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/20181010061456.22238-2-jgross@suse.com Signed-off-by: Ingo Molnar --- arch/x86/xen/enlighten_pvh.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86') diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c index c85d1a88f476..f7f77023288a 100644 --- a/arch/x86/xen/enlighten_pvh.c +++ b/arch/x86/xen/enlighten_pvh.c @@ -75,7 +75,7 @@ static void __init init_pvh_bootparams(void) * Version 2.12 supports Xen entry point but we will use default x86/PC * environment (i.e. hardware_subarch 0). */ - pvh_bootparams.hdr.version = 0x212; + pvh_bootparams.hdr.version = (2 << 8) | 12; pvh_bootparams.hdr.type_of_loader = (9 << 4) | 0; /* Xen loader */ x86_init.acpi.get_root_pointer = pvh_get_root_pointer; -- cgit v1.2.3-59-g8ed1b From ae7e1238e68f2a472a125673ab506d49158c1889 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Wed, 10 Oct 2018 08:14:55 +0200 Subject: x86/boot: Add ACPI RSDP address to setup_header Xen PVH guests receive the address of the RSDP table from Xen. In order to support booting a Xen PVH guest via Grub2 using the standard x86 boot entry we need a way for Grub2 to pass the RSDP address to the kernel. For this purpose expand the struct setup_header to hold the physical address of the RSDP address. Being zero means it isn't specified and has to be located the legacy way (searching through low memory or EBDA). While documenting the new setup_header layout and protocol version 2.14 add the missing documentation of protocol version 2.13. There are Grub2 versions in several distros with a downstream patch violating the boot protocol by writing past the end of setup_header. This requires another update of the boot protocol to enable the kernel to distinguish between a specified RSDP address and one filled with garbage by such a broken Grub2. From protocol 2.14 on Grub2 will write the version it is supporting (but never a higher value than found to be supported by the kernel) ored with 0x8000 to the version field of setup_header. This enables the kernel to know up to which field Grub2 has written information to. All fields after that are supposed to be clobbered. Signed-off-by: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: boris.ostrovsky@oracle.com Cc: bp@alien8.de Cc: corbet@lwn.net Cc: linux-doc@vger.kernel.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/20181010061456.22238-3-jgross@suse.com Signed-off-by: Ingo Molnar --- Documentation/x86/boot.txt | 32 +++++++++++++++++++++++++++++++- arch/x86/boot/header.S | 6 +++++- arch/x86/include/asm/x86_init.h | 2 ++ arch/x86/include/uapi/asm/bootparam.h | 4 ++++ arch/x86/kernel/head32.c | 1 + arch/x86/kernel/head64.c | 2 ++ arch/x86/kernel/setup.c | 17 +++++++++++++++++ 7 files changed, 62 insertions(+), 2 deletions(-) (limited to 'arch/x86') diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt index 5e9b826b5f62..7727db8f94bc 100644 --- a/Documentation/x86/boot.txt +++ b/Documentation/x86/boot.txt @@ -61,6 +61,18 @@ Protocol 2.12: (Kernel 3.8) Added the xloadflags field and extension fields to struct boot_params for loading bzImage and ramdisk above 4G in 64bit. +Protocol 2.13: (Kernel 3.14) Support 32- and 64-bit flags being set in + xloadflags to support booting a 64-bit kernel from 32-bit + EFI + +Protocol 2.14: (Kernel 4.20) Added acpi_rsdp_addr holding the physical + address of the ACPI RSDP table. + The bootloader updates version with: + 0x8000 | min(kernel-version, bootloader-version) + kernel-version being the protocol version supported by + the kernel and bootloader-version the protocol version + supported by the bootloader. + **** MEMORY LAYOUT The traditional memory map for the kernel loader, used for Image or @@ -197,6 +209,7 @@ Offset Proto Name Meaning 0258/8 2.10+ pref_address Preferred loading address 0260/4 2.10+ init_size Linear memory required during initialization 0264/4 2.11+ handover_offset Offset of handover entry point +0268/8 2.14+ acpi_rsdp_addr Physical address of RSDP table (1) For backwards compatibility, if the setup_sects field contains 0, the real value is 4. @@ -309,7 +322,7 @@ Protocol: 2.00+ Contains the magic number "HdrS" (0x53726448). Field name: version -Type: read +Type: modify Offset/size: 0x206/2 Protocol: 2.00+ @@ -317,6 +330,12 @@ Protocol: 2.00+ e.g. 0x0204 for version 2.04, and 0x0a11 for a hypothetical version 10.17. + Up to protocol version 2.13 this information is only read by the + bootloader. From protocol version 2.14 onwards the bootloader will + write the used protocol version or-ed with 0x8000 to the field. The + used protocol version will be the minimum of the supported protocol + versions of the bootloader and the kernel. + Field name: realmode_swtch Type: modify (optional) Offset/size: 0x208/4 @@ -744,6 +763,17 @@ Offset/size: 0x264/4 See EFI HANDOVER PROTOCOL below for more details. +Field name: acpi_rsdp_addr +Type: write +Offset/size: 0x268/8 +Protocol: 2.14+ + + This field can be set by the boot loader to tell the kernel the + physical address of the ACPI RSDP table. + + A value of 0 indicates the kernel should fall back to the standard + methods to locate the RSDP. + **** THE IMAGE CHECKSUM diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S index 850b8762e889..4c881c850125 100644 --- a/arch/x86/boot/header.S +++ b/arch/x86/boot/header.S @@ -300,7 +300,7 @@ _start: # Part 2 of the header, from the old setup.S .ascii "HdrS" # header signature - .word 0x020d # header version number (>= 0x0105) + .word 0x020e # header version number (>= 0x0105) # or else old loadlin-1.5 will fail) .globl realmode_swtch realmode_swtch: .word 0, 0 # default_switch, SETUPSEG @@ -558,6 +558,10 @@ pref_address: .quad LOAD_PHYSICAL_ADDR # preferred load addr init_size: .long INIT_SIZE # kernel initialization size handover_offset: .long 0 # Filled in by build.c +acpi_rsdp_addr: .quad 0 # 64-bit physical pointer to the + # ACPI RSDP table, added with + # version 2.14 + # End of setup header ##################################################### .section ".entrytext", "ax" diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h index b85a7c54c6a1..0f842104862c 100644 --- a/arch/x86/include/asm/x86_init.h +++ b/arch/x86/include/asm/x86_init.h @@ -303,4 +303,6 @@ extern void x86_init_noop(void); extern void x86_init_uint_noop(unsigned int unused); extern bool x86_pnpbios_disabled(void); +void x86_verify_bootdata_version(void); + #endif diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h index a06cbf019744..22f89d040ddd 100644 --- a/arch/x86/include/uapi/asm/bootparam.h +++ b/arch/x86/include/uapi/asm/bootparam.h @@ -16,6 +16,9 @@ #define RAMDISK_PROMPT_FLAG 0x8000 #define RAMDISK_LOAD_FLAG 0x4000 +/* version flags */ +#define VERSION_WRITTEN 0x8000 + /* loadflags */ #define LOADED_HIGH (1<<0) #define KASLR_FLAG (1<<1) @@ -86,6 +89,7 @@ struct setup_header { __u64 pref_address; __u32 init_size; __u32 handover_offset; + __u64 acpi_rsdp_addr; } __attribute__((packed)); struct sys_desc_table { diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c index ec6fefbfd3c0..76fa3b836598 100644 --- a/arch/x86/kernel/head32.c +++ b/arch/x86/kernel/head32.c @@ -37,6 +37,7 @@ asmlinkage __visible void __init i386_start_kernel(void) cr4_init_shadow(); sanitize_boot_params(&boot_params); + x86_verify_bootdata_version(); x86_early_init_platform_quirks(); diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index ddee1f0870c4..5dc377dc9d7b 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -457,6 +457,8 @@ void __init x86_64_start_reservations(char *real_mode_data) if (!boot_params.hdr.version) copy_bootdata(__va(real_mode_data)); + x86_verify_bootdata_version(); + x86_early_init_platform_quirks(); switch (boot_params.hdr.hardware_subarch) { diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index b4866badb235..8e226b7a1753 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1281,6 +1281,23 @@ void __init setup_arch(char **cmdline_p) unwind_init(); } +/* + * From boot protocol 2.14 onwards we expect the bootloader to set the + * version to "0x8000 | ". In case we find a version >= 2.14 + * without the 0x8000 we assume the boot loader supports 2.13 only and + * reset the version accordingly. The 0x8000 flag is removed in any case. + */ +void __init x86_verify_bootdata_version(void) +{ + if (boot_params.hdr.version & VERSION_WRITTEN) + boot_params.hdr.version &= ~VERSION_WRITTEN; + else if (boot_params.hdr.version >= 0x020e) + boot_params.hdr.version = 0x020d; + + if (boot_params.hdr.version < 0x020e) + boot_params.hdr.acpi_rsdp_addr = 0; +} + #ifdef CONFIG_X86_32 static struct resource video_ram_resource = { -- cgit v1.2.3-59-g8ed1b From e7b66d16fe41722350ba87f5788052ef53ee28bb Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Wed, 10 Oct 2018 08:14:56 +0200 Subject: x86/acpi, x86/boot: Take RSDP address for boot params if available In case the RSDP address in struct boot_params is specified don't try to find the table by searching, but take the address directly as set by the boot loader. Signed-off-by: Juergen Gross Cc: Andy Lutomirski Cc: Andy Shevchenko Cc: Baoquan He Cc: Borislav Petkov Cc: Jia Zhang Cc: Len Brown Cc: Linus Torvalds Cc: Pavel Machek Cc: Pavel Tatashin Cc: Peter Zijlstra Cc: Rafael J. Wysocki Cc: Thomas Gleixner Cc: boris.ostrovsky@oracle.com Cc: linux-kernel@vger.kernel.org Cc: linux-pm@vger.kernel.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/20181010061456.22238-4-jgross@suse.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/acpi.h | 7 +++++++ arch/x86/kernel/acpi/boot.c | 6 ++++++ arch/x86/kernel/x86_init.c | 3 +-- 3 files changed, 14 insertions(+), 2 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h index a303d7b7d763..2f01eb4d6208 100644 --- a/arch/x86/include/asm/acpi.h +++ b/arch/x86/include/asm/acpi.h @@ -142,6 +142,8 @@ static inline u64 acpi_arch_get_root_pointer(void) void acpi_generic_reduced_hw_init(void); +u64 x86_default_get_root_pointer(void); + #else /* !CONFIG_ACPI */ #define acpi_lapic 0 @@ -153,6 +155,11 @@ static inline void disable_acpi(void) { } static inline void acpi_generic_reduced_hw_init(void) { } +static inline u64 x86_default_get_root_pointer(void) +{ + return 0; +} + #endif /* !CONFIG_ACPI */ #define ARCH_HAS_POWER_INIT 1 diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 3b20607d581b..e8fea7ffa306 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -48,6 +48,7 @@ #include #include #include +#include #include "sleep.h" /* To include x86_acpi_suspend_lowlevel */ static int __initdata acpi_force = 0; @@ -1771,3 +1772,8 @@ void __init arch_reserve_mem_area(acpi_physical_address addr, size_t size) e820__range_add(addr, size, E820_TYPE_ACPI); e820__update_table_print(); } + +u64 x86_default_get_root_pointer(void) +{ + return boot_params.hdr.acpi_rsdp_addr; +} diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c index 2792b5573818..50a2b492fdd6 100644 --- a/arch/x86/kernel/x86_init.c +++ b/arch/x86/kernel/x86_init.c @@ -31,7 +31,6 @@ static int __init iommu_init_noop(void) { return 0; } static void iommu_shutdown_noop(void) { } static bool __init bool_x86_init_noop(void) { return false; } static void x86_op_int_noop(int cpu) { } -static u64 u64_x86_init_noop(void) { return 0; } /* * The platform setup functions are preset with the default functions @@ -96,7 +95,7 @@ struct x86_init_ops x86_init __initdata = { }, .acpi = { - .get_root_pointer = u64_x86_init_noop, + .get_root_pointer = x86_default_get_root_pointer, .reduced_hw_early_init = acpi_generic_reduced_hw_init, }, }; -- cgit v1.2.3-59-g8ed1b