From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Peter Jones <pjones@redhat.com>

Date: Fri, 12 Jul 2019 09:53:32 +0200

Subject: [PATCH] x86-efi: Use bounce buffers for reading to addresses > 4GB

Lots of machines apparently can't DMA correctly above 4GB during UEFI,

so use bounce buffers for the initramfs read.

Signed-off-by: Peter Jones <pjones@redhat.com>

(cherry picked from commit 7765a790dee00f2e0d414cf3a3d016c493cf0d9b)

Conflicts:

	grub-core/loader/i386/efi/linux.c

        git cherry-pick thought delete of prior def of MIN was a

	conflict.

Signed-off-by: Lenny Szubowicz <lszubowi@redhat.com>

---

 grub-core/loader/i386/efi/linux.c | 52 +++++++++++++++++++++++++++++++++------

 1 file changed, 45 insertions(+), 7 deletions(-)

diff --git a/grub-core/loader/i386/efi/linux.c b/grub-core/loader/i386/efi/linux.c

index c5fdf522b..73cd838e9 100644

--- a/grub-core/loader/i386/efi/linux.c

+++ b/grub-core/loader/i386/efi/linux.c

@@ -37,11 +37,16 @@ static grub_dl_t my_mod;

 static int loaded;

 static void *kernel_mem;

 static grub_uint64_t kernel_size;

-static grub_uint8_t *initrd_mem;

+static void *initrd_mem;

 static grub_uint32_t handover_offset;

 struct linux_kernel_params *params;

 static char *linux_cmdline;

+#define MIN(a, b) \

+  ({ typeof (a) _a = (a); \

+     typeof (b) _b = (b); \

+     _a < _b ? _a : _b; })

+

 #define BYTES_TO_PAGES(bytes)   (((bytes) + 0xfff) >> 12)

 static grub_err_t

@@ -75,6 +80,44 @@ grub_linuxefi_unload (void)

   return GRUB_ERR_NONE;

 }

+#define BOUNCE_BUFFER_MAX 0x10000000ull

+

+static grub_ssize_t

+read(grub_file_t file, grub_uint8_t *bufp, grub_size_t len)

+{

+  grub_ssize_t bufpos = 0;

+  static grub_size_t bbufsz = 0;

+  static char *bbuf = NULL;

+

+  if (bbufsz == 0)

+    bbufsz = MIN(BOUNCE_BUFFER_MAX, len);

+

+  while (!bbuf && bbufsz)

+    {

+      bbuf = grub_malloc(bbufsz);

+      if (!bbuf)

+	bbufsz >>= 1;

+    }

+  if (!bbuf)

+    grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("cannot allocate bounce buffer"));

+

+  while (bufpos < (long long)len)

+    {

+      grub_ssize_t sz;

+

+      sz = grub_file_read (file, bbuf, MIN(bbufsz, len - bufpos));

+      if (sz < 0)

+	return sz;

+      if (sz == 0)

+	break;

+

+      grub_memcpy(bufp + bufpos, bbuf, sz);

+      bufpos += sz;

+    }

+

+  return bufpos;

+}

+

 static grub_err_t

 grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),

                  int argc, char *argv[])

@@ -133,7 +176,7 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),

   for (i = 0; i < nfiles; i++)

     {

       grub_ssize_t cursize = grub_file_size (files[i]);

-      if (grub_file_read (files[i], ptr, cursize) != cursize)

+      if (read (files[i], ptr, cursize) != cursize)

         {

           if (!grub_errno)

             grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),

@@ -161,11 +204,6 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),

   return grub_errno;

 }

-#define MIN(a, b) \

-  ({ typeof (a) _a = (a); \

-     typeof (b) _b = (b); \

-     _a < _b ? _a : _b; })

-

 static grub_err_t

 grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

 		int argc, char *argv[])