grub2/0118-x86-efi-Use-bounce-buffers-for-reading-to-addresses-.patch

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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>
---
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 33e981e76e7..2f0336809e7 100644
--- a/grub-core/loader/i386/efi/linux.c
+++ b/grub-core/loader/i386/efi/linux.c
@@ -35,11 +35,16 @@ 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
@@ -73,6 +78,44 @@ 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[])
@@ -126,7 +169,7 @@ 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"),
@@ -152,11 +195,6 @@ 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[])