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https://abf.rosa.ru/djam/kernel-5.15.git
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137 lines
4.2 KiB
Diff
137 lines
4.2 KiB
Diff
From f2c459c92298deb7054414bd857fe26723be5dab Mon Sep 17 00:00:00 2001
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From: Alexey Sheplyakov <asheplyakov@altlinux.org>
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Date: Tue, 10 Nov 2020 19:05:39 +0400
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Subject: [PATCH 607/631] Fixed secondary CPUs boot on BE-M1000 SoC
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The secure world on BE-M1000 SoC denies execution attempts outside of
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the ranges [0x80000000, 0x8FFFFFFF] [0xA0000000, 0xBFFFFFFF]. Thus
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PSCI calls to boot secondary CPUs fail unless the kernel image resides
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in one of these (physical) address ranges. However BE-M1000's UEFI
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PE/COFF loader puts the kernel into the forbidden range. Since the alignment
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is good enough EFI stub does not try to relocate the kernel. As a result
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secondary CPUs fail to boot.
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Relocation to a random address is not going to work either. Therefore
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automatically disable kaslr on "known bad" systems (for now only BE-M1000
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ones) and forcibly relocate the kernel to a low(er) address.
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---
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drivers/firmware/efi/libstub/arm64-stub.c | 61 ++++++++++++++++++++++-
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1 file changed, 60 insertions(+), 1 deletion(-)
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diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c
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index c1b57dfb1277..411f1546d171 100644
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--- a/drivers/firmware/efi/libstub/arm64-stub.c
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+++ b/drivers/firmware/efi/libstub/arm64-stub.c
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@@ -11,6 +11,7 @@
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#include <asm/efi.h>
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#include <asm/memory.h>
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#include <asm/sections.h>
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+#include <linux/libfdt.h>
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#include <asm/sysreg.h>
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#include "efistub.h"
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@@ -34,6 +35,31 @@ efi_status_t check_platform_features(void)
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return EFI_SUCCESS;
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}
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+static const char* machines_need_low_alloc[] = {
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+ "baikal,baikal-m",
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+};
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+
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+static bool need_low_alloc(void) {
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+ size_t i;
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+ const void *fdt;
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+ const char *match;
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+
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+ fdt = get_efi_config_table(DEVICE_TREE_GUID);
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+ if (!fdt) {
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+ efi_info("failed to retrive FDT from EFI\n");
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+ return false;
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+ }
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+
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+ for (i = 0; i < ARRAY_SIZE(machines_need_low_alloc); i++) {
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+ match = machines_need_low_alloc[i];
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+ if (fdt_node_check_compatible(fdt, 0, match) == 0) {
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+ efi_info("machine %s: forcing kernel relocation to low address\n", match);
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+ return true;
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+ }
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+ }
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+ return false;
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+}
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+
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/*
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* Distro versions of GRUB may ignore the BSS allocation entirely (i.e., fail
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* to provide space, and fail to zero it). Check for this condition by double
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@@ -79,6 +105,19 @@ static bool check_image_region(u64 base, u64 size)
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return ret;
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}
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+static inline efi_status_t efi_low_alloc(unsigned long size, unsigned long align,
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+ unsigned long *addr)
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+{
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+ /*
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+ * Don't allocate at 0x0. It will confuse code that
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+ * checks pointers against NULL. Skip the first 8
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+ * bytes so we start at a nice even number.
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+ */
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+ return efi_low_alloc_above(size, align, addr, 0x8);
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+}
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+
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+
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+
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efi_status_t handle_kernel_image(unsigned long *image_addr,
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unsigned long *image_size,
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unsigned long *reserve_addr,
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@@ -88,6 +127,13 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
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efi_status_t status;
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unsigned long kernel_size, kernel_memsize = 0;
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u32 phys_seed = 0;
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+ bool force_low_reloc = need_low_alloc();
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+ if (force_low_reloc) {
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+ if (!efi_nokaslr) {
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+ efi_info("booting on a broken firmware, KASLR will be disabled\n");
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+ efi_nokaslr = true;
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+ }
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+ }
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/*
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* Although relocatable kernels can fix up the misalignment with
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@@ -112,7 +158,8 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
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efi_nokaslr = true;
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}
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} else {
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- efi_info("KASLR disabled on kernel command line\n");
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+ if (!force_low_reloc)
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+ efi_info("KASLR disabled on kernel command line\n");
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}
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}
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@@ -138,6 +185,15 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
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status = EFI_OUT_OF_RESOURCES;
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}
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+ if (force_low_reloc) {
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+ status = efi_low_alloc(*reserve_size,
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+ min_kimg_align(),
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+ reserve_addr);
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+ if (status != EFI_SUCCESS) {
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+ efi_err("Failed to relocate kernel, expect secondary CPUs boot failure\n");
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+ }
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+ }
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+
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if (status != EFI_SUCCESS) {
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if (!check_image_region((u64)_text, kernel_memsize)) {
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efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI memory region\n");
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@@ -162,6 +218,9 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
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}
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*image_addr = *reserve_addr;
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+ if (efi_nokaslr) {
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+ efi_info("relocating kernel to 0x%lx\n", *image_addr);
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+ }
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memcpy((void *)*image_addr, _text, kernel_size);
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return EFI_SUCCESS;
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--
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2.31.1
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