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[tip:efi/core] efi/arm64: Check for h/w support before booting a >4 KB granular kernel

From tip-bot for Ard Biesheuvel <tipbot@zytor.com>@zytor.com
Newsgroups linux.kernel
Subject [tip:efi/core] efi/arm64: Check for h/w support before booting a >4 KB granular kernel
Date 2016-02-23 10:30 +0100
Message-ID <r5hs6-3h5-3@gated-at.bofh.it> (permalink)
References <r39yH-6rV-41@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Commit-ID:  42b55734030c1f724d5f47aeb872e2cccd650d79
Gitweb:     http://git.kernel.org/tip/42b55734030c1f724d5f47aeb872e2cccd650d79
Author:     Ard Biesheuvel <ard.biesheuvel@linaro.org>
AuthorDate: Wed, 17 Feb 2016 12:36:02 +0000
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 22 Feb 2016 08:26:27 +0100

efi/arm64: Check for h/w support before booting a >4 KB granular kernel

A kernel built with support for a page size that is not supported by the
hardware it runs on cannot boot to a state where it can inform the user
about the failure.

If we happen to be booting via UEFI, we can fail gracefully so check
if the currently configured page size is supported by the hardware before
entering the kernel proper. Note that UEFI mandates support for 4 KB pages,
so in that case, no check is needed.

Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1455712566-16727-10-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 drivers/firmware/efi/libstub/arm64-stub.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c
index 9e03427..047fc34 100644
--- a/drivers/firmware/efi/libstub/arm64-stub.c
+++ b/drivers/firmware/efi/libstub/arm64-stub.c
@@ -12,6 +12,26 @@
 #include <linux/efi.h>
 #include <asm/efi.h>
 #include <asm/sections.h>
+#include <asm/sysreg.h>
+
+efi_status_t check_platform_features(efi_system_table_t *sys_table_arg)
+{
+	u64 tg;
+
+	/* UEFI mandates support for 4 KB granularity, no need to check */
+	if (IS_ENABLED(CONFIG_ARM64_4K_PAGES))
+		return EFI_SUCCESS;
+
+	tg = (read_cpuid(ID_AA64MMFR0_EL1) >> ID_AA64MMFR0_TGRAN_SHIFT) & 0xf;
+	if (tg != ID_AA64MMFR0_TGRAN_SUPPORTED) {
+		if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
+			pr_efi_err(sys_table_arg, "This 64 KB granular kernel is not supported by your CPU\n");
+		else
+			pr_efi_err(sys_table_arg, "This 16 KB granular kernel is not supported by your CPU\n");
+		return EFI_UNSUPPORTED;
+	}
+	return EFI_SUCCESS;
+}
 
 efi_status_t handle_kernel_image(efi_system_table_t *sys_table_arg,
 				 unsigned long *image_addr,

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Thread

[GIT PULL 00/13] EFI changes for v4.6 part 2 Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-17 13:40 +0100
  [PATCH 08/13] efi/arm: Check for LPAE support before booting a LPAE kernel Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-17 13:40 +0100
    [tip:efi/core] efi/arm: Check for LPAE support before booting a LPAE kernel tip-bot for Ard Biesheuvel <tipbot@zytor.com>@zytor.com - 2016-02-23 10:30 +0100
  [PATCH 11/13] x86/mm/pageattr: Don't implicitly allow _PAGE_RW in kernel_map_pages_in_pgd() Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-17 13:40 +0100
    [tip:efi/core] x86/mm/pat: Don't implicitly allow _PAGE_RW in kernel_map_pages_in_pgd() tip-bot for Sai Praneeth <tipbot@zytor.com>@zytor.com - 2016-02-23 10:20 +0100
  [PATCH 05/13] arm64: vmlinux.lds.S: Handle .init.rodata.xxx and .init.bss sections Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-17 13:40 +0100
    [tip:efi/core] arm64/vmlinux.lds.S: Handle .init.rodata.xxx and .init.bss sections tip-bot for Ard Biesheuvel <tipbot@zytor.com>@zytor.com - 2016-02-23 10:30 +0100
  [PATCH 03/13] x86/mm/pageattr: Use _PAGE_GLOBAL bit for EFI page table mappings Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-17 13:40 +0100
    [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page table mappings tip-bot for Sai Praneeth <tipbot@zytor.com>@zytor.com - 2016-02-23 10:20 +0100
      Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Andy Lutomirski <luto@amacapital.net> - 2016-02-23 18:50 +0100
        Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Linus Torvalds <torvalds@linux-foundation.org> - 2016-02-23 19:10 +0100
          Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Borislav Petkov <bp@alien8.de> - 2016-02-23 19:20 +0100
          Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page table mappings "H. Peter Anvin" <hpa@zytor.com> - 2016-02-24 03:20 +0100
          Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page table mappings "H. Peter Anvin" <hpa@zytor.com> - 2016-02-24 03:20 +0100
          Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Ingo Molnar <mingo@kernel.org> - 2016-02-25 10:00 +0100
        Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com> - 2016-02-24 02:00 +0100
          Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Andy Lutomirski <luto@amacapital.net> - 2016-02-24 03:50 +0100
            Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-24 15:20 +0100
              Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Borislav Petkov <bp@alien8.de> - 2016-02-24 17:30 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Andy Lutomirski <luto@amacapital.net> - 2016-02-24 17:40 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Linus Torvalds <torvalds@linux-foundation.org> - 2016-02-24 20:00 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-24 20:50 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Andy Lutomirski <luto@amacapital.net> - 2016-02-24 21:00 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Sylvain Chouleur <sylvain.chouleur@gmail.com> - 2016-02-29 12:00 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Matt Fleming <matt@codeblueprint.co.uk> - 2016-03-02 12:30 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-24 20:40 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Andy Lutomirski <luto@amacapital.net> - 2016-02-24 21:00 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Ingo Molnar <mingo@kernel.org> - 2016-02-25 10:10 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-25 16:30 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Andy Lutomirski <luto@amacapital.net> - 2016-02-24 17:50 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Borislav Petkov <bp@alien8.de> - 2016-02-24 17:50 +0100
              Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Andy Lutomirski <luto@amacapital.net> - 2016-02-24 17:50 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-25 17:10 +0100
  [PATCH 07/13] efi/arm-init: Use read-only early mappings Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-17 13:40 +0100
    [tip:efi/core] efi/arm-init: Use read-only early mappings tip-bot for Ard Biesheuvel <tipbot@zytor.com>@zytor.com - 2016-02-23 10:30 +0100
  [PATCH 06/13] efi/efistub: Prevent __init annotations from being used Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-17 13:40 +0100
    [tip:efi/core] efi/efistub: Prevent __init annotations from being used tip-bot for Ard Biesheuvel <tipbot@zytor.com>@zytor.com - 2016-02-23 10:10 +0100
  [PATCH 02/13] efi/runtime-wrappers: Run UEFI Runtime Services with interrupts enabled Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-17 13:40 +0100
    [tip:efi/core] efi/runtime-wrappers: Run UEFI Runtime Services with interrupts enabled tip-bot for Ard Biesheuvel <tipbot@zytor.com>@zytor.com - 2016-02-23 10:30 +0100
  [PATCH 13/13] x86/efi: Only map kernel text for EFI mixed mode Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-17 13:40 +0100
    [tip:efi/core] x86/efi: Only map kernel text for EFI mixed mode tip-bot for Sai Praneeth <tipbot@zytor.com>@zytor.com - 2016-02-23 10:20 +0100
  [PATCH 12/13] x86/efi: Map EFI_MEMORY_{XP,RO} memory region bits to EFI page tables Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-17 13:40 +0100
    [tip:efi/core] x86/efi: Map EFI_MEMORY_{XP,RO} memory region bits to EFI page tables tip-bot for Sai Praneeth <tipbot@zytor.com>@zytor.com - 2016-02-23 10:20 +0100
  [PATCH 10/13] efi/arm*: Perform hardware compatibility check Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-17 13:40 +0100
    [tip:efi/core] efi/arm*: Perform hardware compatibility check tip-bot for Ard Biesheuvel <tipbot@zytor.com>@zytor.com - 2016-02-23 10:30 +0100
  [PATCH 09/13] efi/arm64: Check for h/w support before booting a >4 KB granule kernel Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-17 13:40 +0100
    [tip:efi/core] efi/arm64: Check for h/w support before booting a >4 KB granular kernel tip-bot for Ard Biesheuvel <tipbot@zytor.com>@zytor.com - 2016-02-23 10:30 +0100
  [PATCH 01/13] efi: Reformat GUID tables to follow the format in UEFI spec Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-17 13:50 +0100
    [tip:efi/core] efi: Reformat GUID tables to follow the format in UEFI spec tip-bot for Peter Jones <tipbot@zytor.com>@zytor.com - 2016-02-23 10:30 +0100

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