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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Peter Jones <pjones@redhat.com>
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Date: Tue, 22 Mar 2022 10:56:21 -0400
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Subject: [PATCH] nx: add memory attribute get/set API
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For NX, we need to set the page access permission attributes for write
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and execute permissions.
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This patch adds two new primitives, grub_set_mem_attrs() and
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grub_clear_mem_attrs(), and associated constant definitions, to be used
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for that purpose.
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For most platforms, it adds a dummy implementation that returns
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GRUB_ERR_NONE.  On EFI platforms, it adds a common helper function,
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grub_efi_status_to_err(), which translates EFI error codes to grub error
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codes, adds headers for the EFI Memory Attribute Protocol (still pending
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standardization), and an implementation of the grub nx primitives using
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it.
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Signed-off-by: Peter Jones <pjones@redhat.com>
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[rharwood: add pjones's none/nyi fixup]
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Signed-off-by: Robbie Harwood <rharwood@redhat.com>
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---
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 grub-core/kern/efi/efi.c |  36 +++++++++++++
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 grub-core/kern/efi/mm.c  | 131 +++++++++++++++++++++++++++++++++++++++++++++++
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 include/grub/efi/api.h   |  25 +++++++++
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 include/grub/efi/efi.h   |   2 +
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 include/grub/mm.h        |  32 ++++++++++++
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 5 files changed, 226 insertions(+)
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diff --git a/grub-core/kern/efi/efi.c b/grub-core/kern/efi/efi.c
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index 7fcca69c17..4ac2b2754e 100644
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--- a/grub-core/kern/efi/efi.c
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+++ b/grub-core/kern/efi/efi.c
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@@ -1096,3 +1096,39 @@ grub_efi_compare_device_paths (const grub_efi_device_path_t *dp1,
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   return 0;
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 }
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+
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+grub_err_t
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+grub_efi_status_to_err (grub_efi_status_t status)
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+{
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+  grub_err_t err;
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+  switch (status)
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+    {
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+    case GRUB_EFI_SUCCESS:
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+      err = GRUB_ERR_NONE;
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+      break;
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+    case GRUB_EFI_INVALID_PARAMETER:
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+    default:
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+      err = GRUB_ERR_BAD_ARGUMENT;
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+      break;
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+    case GRUB_EFI_OUT_OF_RESOURCES:
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+      err = GRUB_ERR_OUT_OF_MEMORY;
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+      break;
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+    case GRUB_EFI_DEVICE_ERROR:
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+      err = GRUB_ERR_IO;
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+      break;
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+    case GRUB_EFI_WRITE_PROTECTED:
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+      err = GRUB_ERR_WRITE_ERROR;
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+      break;
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+    case GRUB_EFI_SECURITY_VIOLATION:
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+      err = GRUB_ERR_ACCESS_DENIED;
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+      break;
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+    case GRUB_EFI_NOT_FOUND:
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+      err = GRUB_ERR_FILE_NOT_FOUND;
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+      break;
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+    case GRUB_EFI_ABORTED:
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+      err = GRUB_ERR_WAIT;
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+      break;
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+    }
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+
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+  return err;
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+}
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diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c
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index e84961d078..2c33758ed7 100644
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--- a/grub-core/kern/efi/mm.c
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+++ b/grub-core/kern/efi/mm.c
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@@ -738,3 +738,134 @@ grub_efi_get_ram_base(grub_addr_t *base_addr)
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   return GRUB_ERR_NONE;
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 }
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 #endif
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+
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+static inline grub_uint64_t
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+grub_mem_attrs_to_uefi_mem_attrs (grub_uint64_t attrs)
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+{
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+  grub_uint64_t ret = GRUB_EFI_MEMORY_RP |
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+		      GRUB_EFI_MEMORY_RO |
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+		      GRUB_EFI_MEMORY_XP;
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+
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+  if (attrs & GRUB_MEM_ATTR_R)
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+    ret &= ~GRUB_EFI_MEMORY_RP;
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+
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+  if (attrs & GRUB_MEM_ATTR_W)
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+    ret &= ~GRUB_EFI_MEMORY_RO;
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+
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+  if (attrs & GRUB_MEM_ATTR_X)
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+    ret &= ~GRUB_EFI_MEMORY_XP;
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+
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+  return ret;
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+}
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+
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+static inline grub_uint64_t
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+uefi_mem_attrs_to_grub_mem_attrs (grub_uint64_t attrs)
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+{
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+  grub_uint64_t ret = GRUB_MEM_ATTR_R |
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+		      GRUB_MEM_ATTR_W |
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+		      GRUB_MEM_ATTR_X;
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+
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+  if (attrs & GRUB_EFI_MEMORY_RP)
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+    ret &= ~GRUB_MEM_ATTR_R;
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+
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+  if (attrs & GRUB_EFI_MEMORY_RO)
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+    ret &= ~GRUB_MEM_ATTR_W;
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+
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+  if (attrs & GRUB_EFI_MEMORY_XP)
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+    ret &= ~GRUB_MEM_ATTR_X;
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+
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+  return ret;
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+}
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+
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+grub_err_t
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+grub_get_mem_attrs (grub_addr_t addr, grub_size_t size, grub_uint64_t *attrs)
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+{
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+  grub_efi_memory_attribute_protocol_t *proto;
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+  grub_efi_physical_address_t physaddr = addr;
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+  grub_efi_guid_t protocol_guid = GRUB_EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID;
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+  grub_efi_status_t efi_status;
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+
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+  proto = grub_efi_locate_protocol (&protocol_guid, 0);
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+  if (!proto)
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+    return GRUB_ERR_NOT_IMPLEMENTED_YET;
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+
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+  if (physaddr & 0xfff || size & 0xfff || size == 0 || attrs == NULL)
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+    {
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+      grub_dprintf ("nx", "%s called on 0x%"PRIxGRUB_ADDR"-0x%"PRIxGRUB_ADDR" and attrs %p\n",
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+		    __func__, physaddr, physaddr+size-1, attrs);
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+      return 0;
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+    }
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+
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+  efi_status = efi_call_4(proto->get_memory_attributes,
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+			  proto, physaddr, size, attrs);
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+  *attrs = uefi_mem_attrs_to_grub_mem_attrs (*attrs);
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+
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+  return grub_efi_status_to_err (efi_status);
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+}
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+
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+grub_err_t
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+grub_update_mem_attrs (grub_addr_t addr, grub_size_t size,
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+		       grub_uint64_t set_attrs, grub_uint64_t clear_attrs)
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+{
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+  grub_efi_memory_attribute_protocol_t *proto;
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+  grub_efi_physical_address_t physaddr = addr;
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+  grub_efi_guid_t protocol_guid = GRUB_EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID;
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+  grub_efi_status_t efi_status = GRUB_EFI_SUCCESS;
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+  grub_uint64_t before = 0, after = 0, uefi_set_attrs, uefi_clear_attrs;
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+  grub_err_t err;
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+
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+  proto = grub_efi_locate_protocol (&protocol_guid, 0);
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+  if (!proto)
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+    return GRUB_ERR_NONE;
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+
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+  err = grub_get_mem_attrs (addr, size, &before);
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+  if (err)
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+    grub_dprintf ("nx", "grub_get_mem_attrs(0x%"PRIxGRUB_ADDR", %"PRIuGRUB_SIZE", %p) -> 0x%x\n",
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+		  addr, size, &before, err);
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+
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+  if (physaddr & 0xfff || size & 0xfff || size == 0)
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+    {
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+      grub_dprintf ("nx", "%s called on 0x%"PRIxGRUB_ADDR"-0x%"PRIxGRUB_ADDR" +%s%s%s -%s%s%s\n",
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+		    __func__, physaddr, physaddr + size - 1,
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+		    (set_attrs & GRUB_MEM_ATTR_R) ? "r" : "",
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+		    (set_attrs & GRUB_MEM_ATTR_W) ? "w" : "",
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+		    (set_attrs & GRUB_MEM_ATTR_X) ? "x" : "",
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+		    (clear_attrs & GRUB_MEM_ATTR_R) ? "r" : "",
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+		    (clear_attrs & GRUB_MEM_ATTR_W) ? "w" : "",
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+		    (clear_attrs & GRUB_MEM_ATTR_X) ? "x" : "");
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+      return 0;
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+    }
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+
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+  uefi_set_attrs = grub_mem_attrs_to_uefi_mem_attrs (set_attrs);
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+  grub_dprintf ("nx", "translating set_attrs from 0x%lx to 0x%lx\n", set_attrs, uefi_set_attrs);
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+  uefi_clear_attrs = grub_mem_attrs_to_uefi_mem_attrs (clear_attrs);
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+  grub_dprintf ("nx", "translating clear_attrs from 0x%lx to 0x%lx\n", clear_attrs, uefi_clear_attrs);
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+  if (uefi_set_attrs)
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+    efi_status = efi_call_4(proto->set_memory_attributes,
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+			    proto, physaddr, size, uefi_set_attrs);
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+  if (efi_status == GRUB_EFI_SUCCESS && uefi_clear_attrs)
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+    efi_status = efi_call_4(proto->clear_memory_attributes,
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+			    proto, physaddr, size, uefi_clear_attrs);
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+
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+  err = grub_get_mem_attrs (addr, size, &after);
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+  if (err)
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+    grub_dprintf ("nx", "grub_get_mem_attrs(0x%"PRIxGRUB_ADDR", %"PRIuGRUB_SIZE", %p) -> 0x%x\n",
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+		  addr, size, &after, err);
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+
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+  grub_dprintf ("nx", "set +%s%s%s -%s%s%s on 0x%"PRIxGRUB_ADDR"-0x%"PRIxGRUB_ADDR" before:%c%c%c after:%c%c%c\n",
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+		(set_attrs & GRUB_MEM_ATTR_R) ? "r" : "",
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+		(set_attrs & GRUB_MEM_ATTR_W) ? "w" : "",
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+		(set_attrs & GRUB_MEM_ATTR_X) ? "x" : "",
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+		(clear_attrs & GRUB_MEM_ATTR_R) ? "r" : "",
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+		(clear_attrs & GRUB_MEM_ATTR_W) ? "w" : "",
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+		(clear_attrs & GRUB_MEM_ATTR_X) ? "x" : "",
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+		addr, addr + size - 1,
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+		(before & GRUB_MEM_ATTR_R) ? 'r' : '-',
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+		(before & GRUB_MEM_ATTR_W) ? 'w' : '-',
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+		(before & GRUB_MEM_ATTR_X) ? 'x' : '-',
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+		(after & GRUB_MEM_ATTR_R) ? 'r' : '-',
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+		(after & GRUB_MEM_ATTR_W) ? 'w' : '-',
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+		(after & GRUB_MEM_ATTR_X) ? 'x' : '-');
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+
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+  return grub_efi_status_to_err (efi_status);
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+}
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diff --git a/include/grub/efi/api.h b/include/grub/efi/api.h
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index f431f49973..464842ba37 100644
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--- a/include/grub/efi/api.h
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+++ b/include/grub/efi/api.h
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@@ -363,6 +363,11 @@
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       { 0x89, 0x29, 0x48, 0xbc, 0xd9, 0x0a, 0xd3, 0x1a } \
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   }
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+#define GRUB_EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID \
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+  { 0xf4560cf6, 0x40ec, 0x4b4a, \
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+    { 0xa1, 0x92, 0xbf, 0x1d, 0x57, 0xd0, 0xb1, 0x89 } \
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+  }
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+
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 struct grub_efi_sal_system_table
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 {
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   grub_uint32_t signature;
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@@ -2102,6 +2107,26 @@ struct grub_efi_ip6_config_manual_address {
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 };
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 typedef struct grub_efi_ip6_config_manual_address grub_efi_ip6_config_manual_address_t;
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+struct grub_efi_memory_attribute_protocol
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+{
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+  grub_efi_status_t (*get_memory_attributes) (
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+			    struct grub_efi_memory_attribute_protocol *this,
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+			    grub_efi_physical_address_t base_address,
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+			    grub_efi_uint64_t length,
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+			    grub_efi_uint64_t *attributes);
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+  grub_efi_status_t (*set_memory_attributes) (
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+			    struct grub_efi_memory_attribute_protocol *this,
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+			    grub_efi_physical_address_t base_address,
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+			    grub_efi_uint64_t length,
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+			    grub_efi_uint64_t attributes);
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+  grub_efi_status_t (*clear_memory_attributes) (
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+			    struct grub_efi_memory_attribute_protocol *this,
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+			    grub_efi_physical_address_t base_address,
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+			    grub_efi_uint64_t length,
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+			    grub_efi_uint64_t attributes);
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+};
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+typedef struct grub_efi_memory_attribute_protocol grub_efi_memory_attribute_protocol_t;
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+
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 #if (GRUB_TARGET_SIZEOF_VOID_P == 4) || defined (__ia64__) \
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   || defined (__aarch64__) || defined (__MINGW64__) || defined (__CYGWIN__) \
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   || defined(__riscv)
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diff --git a/include/grub/efi/efi.h b/include/grub/efi/efi.h
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index ec52083c49..34825c4adc 100644
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--- a/include/grub/efi/efi.h
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+++ b/include/grub/efi/efi.h
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@@ -164,4 +164,6 @@ struct grub_net_card;
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 grub_efi_handle_t
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 grub_efinet_get_device_handle (struct grub_net_card *card);
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+grub_err_t EXPORT_FUNC(grub_efi_status_to_err) (grub_efi_status_t status);
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+
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 #endif /* ! GRUB_EFI_EFI_HEADER */
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diff --git a/include/grub/mm.h b/include/grub/mm.h
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index 9c38dd3ca5..d81623d226 100644
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--- a/include/grub/mm.h
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+++ b/include/grub/mm.h
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@@ -22,6 +22,7 @@
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 #include <grub/types.h>
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 #include <grub/symbol.h>
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+#include <grub/err.h>
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 #include <config.h>
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 #ifndef NULL
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@@ -38,6 +39,37 @@ void *EXPORT_FUNC(grub_realloc) (void *ptr, grub_size_t size);
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 void *EXPORT_FUNC(grub_memalign) (grub_size_t align, grub_size_t size);
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 #endif
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+#define GRUB_MEM_ATTR_R	0x0000000000000004LLU
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+#define GRUB_MEM_ATTR_W	0x0000000000000002LLU
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+#define GRUB_MEM_ATTR_X	0x0000000000000001LLU
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+
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+#ifdef GRUB_MACHINE_EFI
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+grub_err_t EXPORT_FUNC(grub_get_mem_attrs) (grub_addr_t addr,
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+					    grub_size_t size,
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+					    grub_uint64_t *attrs);
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+grub_err_t EXPORT_FUNC(grub_update_mem_attrs) (grub_addr_t addr,
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+					       grub_size_t size,
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+					       grub_uint64_t set_attrs,
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+					       grub_uint64_t clear_attrs);
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+#else /* !GRUB_MACHINE_EFI */
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+static inline grub_err_t
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+grub_get_mem_attrs (grub_addr_t addr __attribute__((__unused__)),
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+		    grub_size_t size __attribute__((__unused__)),
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+		    grub_uint64_t *attrs __attribute__((__unused__)))
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+{
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+  return GRUB_ERR_NONE;
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+}
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+
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+static inline grub_err_t
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+grub_update_mem_attrs (grub_addr_t addr __attribute__((__unused__)),
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+		       grub_size_t size __attribute__((__unused__)),
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+		       grub_uint64_t set_attrs __attribute__((__unused__)),
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+		       grub_uint64_t clear_attrs __attribute__((__unused__)))
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+{
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+  return GRUB_ERR_NONE;
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+}
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+#endif /* GRUB_MACHINE_EFI */
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+
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 void grub_mm_check_real (const char *file, int line);
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 #define grub_mm_check() grub_mm_check_real (GRUB_FILE, __LINE__);
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