grub2/0257-Correct-BSS-zeroing-on-aarch64.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jeremy Linton <jeremy.linton@arm.com>
Date: Tue, 16 Apr 2024 13:26:55 -0600
Subject: [PATCH] Correct BSS zeroing on aarch64

The aarch64 loader doesn't use efi bootservices, and
therefor it has a very minimal loader which makes a lot
of assumptions about the kernel layout. With the ZBOOT
changes, the layout has changed a bit and we not should
really be parsing the PE sections to determine how much
data to copy, otherwise the BSS won't be setup properly.

This code still makes a lot of assumptions about the
the kernel layout, so its far from ideal, but it works.

Resolves: rhbz#2125069

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
---
 grub-core/loader/efi/linux.c | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/grub-core/loader/efi/linux.c b/grub-core/loader/efi/linux.c
index ecaa8c18c4d..55c5c8600d4 100644
--- a/grub-core/loader/efi/linux.c
+++ b/grub-core/loader/efi/linux.c
@@ -517,10 +517,12 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
 static grub_err_t
 parse_pe_header (void *kernel, grub_uint64_t *total_size,
 		 grub_uint32_t *entry_offset,
-		 grub_uint32_t *alignment)
+		 grub_uint32_t *alignment, grub_uint32_t *code_size)
 {
   struct linux_arch_kernel_header *lh = kernel;
   struct grub_armxx_linux_pe_header *pe;
+  grub_uint16_t i;
+  struct grub_pe32_section_table *sections;
 
   pe = (void *)((unsigned long)kernel + lh->hdr_offset);
 
@@ -530,6 +532,19 @@ parse_pe_header (void *kernel, grub_uint64_t *total_size,
   *total_size   = pe->opt.image_size;
   *entry_offset = pe->opt.entry_addr;
   *alignment    = pe->opt.section_alignment;
+  *code_size    = pe->opt.section_alignment;
+
+  sections = (struct grub_pe32_section_table *) ((char *)&pe->opt +
+						 pe->coff.optional_header_size);
+  grub_dprintf ("linux", "num_sections     : %d\n",  pe->coff.num_sections );
+  for (i = 0 ; i < pe->coff.num_sections; i++)
+    {
+      grub_dprintf ("linux", "raw_size   : %lld\n",
+		    (long long) sections[i].raw_data_size);
+      grub_dprintf ("linux", "virt_size  : %lld\n",
+		    (long long) sections[i].virtual_size);
+      *code_size += sections[i].raw_data_size;
+    }
 
   return GRUB_ERR_NONE;
 }
@@ -543,6 +558,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
   struct linux_arch_kernel_header lh;
   grub_off_t filelen;
   grub_uint32_t align;
+  grub_uint32_t code_size;
   void *kernel = NULL;
   grub_err_t err;
 
@@ -610,11 +626,12 @@ fallback:
     }
 
 #if !defined(__i386__) && !defined(__x86_64__)
-  if (parse_pe_header (kernel, &kernel_size, &handover_offset, &align) != GRUB_ERR_NONE)
+  if (parse_pe_header (kernel, &kernel_size, &handover_offset, &align, &code_size) != GRUB_ERR_NONE)
     goto fail;
   grub_dprintf ("linux", "kernel mem size     : %lld\n", (long long) kernel_size);
   grub_dprintf ("linux", "kernel entry offset : %d\n", handover_offset);
   grub_dprintf ("linux", "kernel alignment    : 0x%x\n", align);
+  grub_dprintf ("linux", "kernel size         : 0x%x\n", code_size);
 
   grub_loader_unset();
 
@@ -629,9 +646,9 @@ fallback:
   kernel_addr = (void *)ALIGN_UP((grub_uint64_t)kernel_alloc_addr, align);
 
   grub_dprintf ("linux", "kernel @ %p\n", kernel_addr);
-  grub_memcpy (kernel_addr, kernel, grub_min(filelen, kernel_size));
-  if (kernel_size > filelen)
-    grub_memset ((char *)kernel_addr + filelen, 0, kernel_size - filelen);
+  grub_memcpy (kernel_addr, kernel, grub_min(code_size, kernel_size));
+  if (kernel_size > code_size)
+    grub_memset ((char *)kernel_addr + code_size, 0, kernel_size - code_size);
   grub_free(kernel);
   kernel = NULL;
 #endif