grub2/0272-efi-split-allocation-policy-for-kernel-vs-initrd-mem.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Peter Jones <pjones@redhat.com>
Date: Mon, 1 Aug 2022 14:24:39 -0400
Subject: [PATCH] efi: split allocation policy for kernel vs initrd memories.

Currently in our kernel allocator, we use the same set of choices for
all of our various kernel and initramfs allocations, though they do not
have exactly the same constraints.

This patch adds the concept of an allocation purpose, which currently
can be KERNEL_MEM or INITRD_MEM, and updates kernel_alloc() calls
appropriately, but does not change any current policy decision.  It
also adds a few debug prints.

Signed-off-by: Peter Jones <pjones@redhat.com>
---
 grub-core/loader/i386/efi/linux.c | 35 +++++++++++++++++++++++++++--------
 1 file changed, 27 insertions(+), 8 deletions(-)

diff --git a/grub-core/loader/i386/efi/linux.c b/grub-core/loader/i386/efi/linux.c
index 8daa070132..e6b8998e5e 100644
--- a/grub-core/loader/i386/efi/linux.c
+++ b/grub-core/loader/i386/efi/linux.c
@@ -55,7 +55,14 @@ struct grub_linuxefi_context {
 
 #define BYTES_TO_PAGES(bytes)   (((bytes) + 0xfff) >> 12)
 
+typedef enum {
+    NO_MEM,
+    KERNEL_MEM,
+    INITRD_MEM,
+} kernel_alloc_purpose_t;
+
 struct allocation_choice {
+    kernel_alloc_purpose_t purpose;
     grub_efi_physical_address_t addr;
     grub_efi_allocate_type_t alloc_type;
 };
@@ -64,6 +71,7 @@ enum {
     KERNEL_PREF_ADDRESS,
     KERNEL_4G_LIMIT,
     KERNEL_NO_LIMIT,
+    INITRD_MAX_ADDRESS,
 };
 
 static struct allocation_choice max_addresses[] =
@@ -71,14 +79,17 @@ static struct allocation_choice max_addresses[] =
     /* the kernel overrides this one with pref_address and
      * GRUB_EFI_ALLOCATE_ADDRESS */
     [KERNEL_PREF_ADDRESS] =
-      { GRUB_EFI_MAX_ALLOCATION_ADDRESS, GRUB_EFI_ALLOCATE_MAX_ADDRESS },
+      { KERNEL_MEM, GRUB_EFI_MAX_ALLOCATION_ADDRESS, GRUB_EFI_ALLOCATE_MAX_ADDRESS },
     /* If the flag in params is set, this one gets changed to be above 4GB. */
     [KERNEL_4G_LIMIT] =
-      { GRUB_EFI_MAX_ALLOCATION_ADDRESS, GRUB_EFI_ALLOCATE_MAX_ADDRESS },
+      { KERNEL_MEM, GRUB_EFI_MAX_ALLOCATION_ADDRESS, GRUB_EFI_ALLOCATE_MAX_ADDRESS },
     /* this one is always below 4GB, which we still *prefer* even if the flag
      * is set. */
     [KERNEL_NO_LIMIT] =
-      { GRUB_EFI_MAX_ALLOCATION_ADDRESS, GRUB_EFI_ALLOCATE_MAX_ADDRESS },
+      { KERNEL_MEM, GRUB_EFI_MAX_ALLOCATION_ADDRESS, GRUB_EFI_ALLOCATE_MAX_ADDRESS },
+    /* this is for the initrd */
+    [INITRD_MAX_ADDRESS] =
+      { INITRD_MEM, GRUB_EFI_MAX_ALLOCATION_ADDRESS, GRUB_EFI_ALLOCATE_MAX_ADDRESS },
     { NO_MEM, 0, 0 }
   };
 static struct allocation_choice saved_addresses[4];
@@ -95,7 +106,8 @@ kernel_free(void *addr, grub_efi_uintn_t size)
 }
 
 static void *
-kernel_alloc(grub_efi_uintn_t size,
+kernel_alloc(kernel_alloc_purpose_t purpose,
+	     grub_efi_uintn_t size,
 	     grub_efi_memory_type_t memtype,
 	     const char * const errmsg)
 {
@@ -108,6 +120,9 @@ kernel_alloc(grub_efi_uintn_t size,
       grub_uint64_t max = max_addresses[i].addr;
       grub_efi_uintn_t pages;
 
+      if (purpose != max_addresses[i].purpose)
+	continue;
+
       /*
        * When we're *not* loading the kernel, or >4GB allocations aren't
        * supported, these entries are basically all the same, so don't re-try
@@ -261,7 +276,8 @@ grub_cmd_initrd (grub_command_t cmd, int argc, char *argv[])
 	}
     }
 
-  initrd_mem = kernel_alloc(size, GRUB_EFI_RUNTIME_SERVICES_DATA,
+  grub_dprintf ("linux", "Trying to allocate initrd mem\n");
+  initrd_mem = kernel_alloc(INITRD_MEM, size, GRUB_EFI_RUNTIME_SERVICES_DATA,
 			    N_("can't allocate initrd"));
   if (initrd_mem == NULL)
     goto fail;
@@ -422,7 +438,8 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
     }
 #endif
 
-  params = kernel_alloc (sizeof(*params), GRUB_EFI_RUNTIME_SERVICES_DATA,
+  params = kernel_alloc (KERNEL_MEM, sizeof(*params),
+			 GRUB_EFI_RUNTIME_SERVICES_DATA,
 			 "cannot allocate kernel parameters");
   if (!params)
     goto fail;
@@ -445,7 +462,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
   grub_dprintf ("linux", "new lh is at %p\n", lh);
 
   grub_dprintf ("linux", "setting up cmdline\n");
-  cmdline = kernel_alloc (lh->cmdline_size + 1,
+  cmdline = kernel_alloc (KERNEL_MEM, lh->cmdline_size + 1,
 			  GRUB_EFI_RUNTIME_SERVICES_DATA,
 			  N_("can't allocate cmdline"));
   if (!cmdline)
@@ -493,7 +510,9 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
   max_addresses[KERNEL_4G_LIMIT].addr = GRUB_EFI_MAX_ALLOCATION_ADDRESS;
   max_addresses[KERNEL_NO_LIMIT].addr = GRUB_EFI_MAX_ALLOCATION_ADDRESS;
   kernel_size = lh->init_size;
-  kernel_mem = kernel_alloc (kernel_size, GRUB_EFI_RUNTIME_SERVICES_CODE,
+  grub_dprintf ("linux", "Trying to allocate kernel mem\n");
+  kernel_mem = kernel_alloc (KERNEL_MEM, kernel_size,
+			     GRUB_EFI_RUNTIME_SERVICES_CODE,
 			     N_("can't allocate kernel"));
   restore_addresses();
   if (!kernel_mem)