* [RFC PATCH] powerpc: Add support for adding an ESM blob to the zImage wrapper
@ 2018-05-31 4:34 Benjamin Herrenschmidt
0 siblings, 0 replies; only message in thread
From: Benjamin Herrenschmidt @ 2018-05-31 4:34 UTC (permalink / raw)
To: linuxppc-dev
For secure VMs, the signing tool will create a ticket called
the "ESM blob" with the signatures of the kernel and initrd
among other things.
This adds support to the wrapper script for adding that
blob via the "-e" option to the zImage.pseries.
It also adds code to the zImage wrapper itself to
retrieve and if necessary relocate the blob, and pass
its address to Linux via the device-tree, to be later
consumed by prom_init.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
arch/powerpc/boot/main.c | 41 ++++++++++++++++++++++++++++++++++
arch/powerpc/boot/ops.h | 2 ++
arch/powerpc/boot/wrapper | 24 +++++++++++++++++---
arch/powerpc/boot/zImage.lds.S | 8 +++++++
4 files changed, 72 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/boot/main.c b/arch/powerpc/boot/main.c
index 78aaf4ffd7ab..2e818ed4a9ef 100644
--- a/arch/powerpc/boot/main.c
+++ b/arch/powerpc/boot/main.c
@@ -150,6 +150,46 @@ static struct addr_range prep_initrd(struct addr_range vmlinux, void *chosen,
return (struct addr_range){(void *)initrd_addr, initrd_size};
}
+#ifdef __powerpc64__
+static void prep_esm_blob(struct addr_range vmlinux, void *chosen)
+{
+ unsigned long esm_blob_addr, esm_blob_size;
+
+ /* Do we have a blob ? */
+ if (_esm_blob_end <= _esm_blob_start)
+ return;
+
+ printf("Attached ESM blob at 0x%p-0x%p\n\r",
+ _esm_blob_start, _esm_blob_end);
+ esm_blob_addr = (unsigned long)_esm_blob_start;
+ esm_blob_size = _esm_blob_end - _esm_blob_start;
+
+ /*
+ * If the initrd is too low it will be clobbered when the
+ * kernel relocates to its final location. In this case,
+ * allocate a safer place and move it.
+ */
+ if (esm_blob_addr < vmlinux.size) {
+ void *old_addr = (void *)esm_blob_addr;
+
+ printf("Allocating 0x%lx bytes for esm_blob ...\n\r",
+ esm_blob_size);
+ esm_blob_addr = (unsigned long)malloc(esm_blob_size);
+ if (!esm_blob_addr)
+ fatal("Can't allocate memory for ESM blob !\n\r");
+ printf("Relocating ESM blob 0x%lx <- 0x%p (0x%lx bytes)\n\r",
+ esm_blob_addr, old_addr, esm_blob_size);
+ memmove((void *)esm_blob_addr, old_addr, esm_blob_size);
+ }
+
+ /* Tell the kernel initrd address via device tree */
+ setprop_val(chosen, "linux,esm-blob-start", (u32)(esm_blob_addr));
+ setprop_val(chosen, "linux,esm-blob-end", (u32)(esm_blob_addr+esm_blob_size));
+}
+#else
+static inline void prep_esm_blob(struct addr_range vmlinux, void *chosen) { }
+#endif
+
/* A buffer that may be edited by tools operating on a zImage binary so as to
* edit the command line passed to vmlinux (by setting /chosen/bootargs).
* The buffer is put in it's own section so that tools may locate it easier.
@@ -218,6 +258,7 @@ void start(void)
vmlinux = prep_kernel();
initrd = prep_initrd(vmlinux, chosen,
loader_info.initrd_addr, loader_info.initrd_size);
+ prep_esm_blob(vmlinux, chosen);
prep_cmdline(chosen);
printf("Finalizing device tree...");
diff --git a/arch/powerpc/boot/ops.h b/arch/powerpc/boot/ops.h
index fad1862f4b2d..1212aca660f2 100644
--- a/arch/powerpc/boot/ops.h
+++ b/arch/powerpc/boot/ops.h
@@ -252,6 +252,8 @@ extern char _initrd_start[];
extern char _initrd_end[];
extern char _dtb_start[];
extern char _dtb_end[];
+extern char _esm_blob_start[];
+extern char _esm_blob_end[];
static inline __attribute__((const))
int __ilog2_u32(u32 n)
diff --git a/arch/powerpc/boot/wrapper b/arch/powerpc/boot/wrapper
index f9141eaec6ff..36b2ad6cd5b7 100755
--- a/arch/powerpc/boot/wrapper
+++ b/arch/powerpc/boot/wrapper
@@ -14,6 +14,7 @@
# -i initrd specify initrd file
# -d devtree specify device-tree blob
# -s tree.dts specify device-tree source file (needs dtc installed)
+# -e esm_blob specify ESM blob for secure images
# -c cache $kernel.strip.gz (use if present & newer, else make)
# -C prefix specify command prefix for cross-building tools
# (strip, objcopy, ld)
@@ -38,6 +39,7 @@ platform=of
initrd=
dtb=
dts=
+esm_blob=
cacheit=
binary=
compression=.gz
@@ -60,9 +62,9 @@ tmpdir=.
usage() {
echo 'Usage: wrapper [-o output] [-p platform] [-i initrd]' >&2
- echo ' [-d devtree] [-s tree.dts] [-c] [-C cross-prefix]' >&2
- echo ' [-D datadir] [-W workingdir] [-Z (gz|xz|none)]' >&2
- echo ' [--no-compression] [vmlinux]' >&2
+ echo ' [-d devtree] [-s tree.dts] [-e esm_blob]' >&2
+ echo ' [-c] [-C cross-prefix] [-D datadir] [-W workingdir]' >&2
+ echo ' [-Z (gz|xz|none)] [--no-compression] [vmlinux]' >&2
exit 1
}
@@ -105,6 +107,11 @@ while [ "$#" -gt 0 ]; do
[ "$#" -gt 0 ] || usage
dtb="$1"
;;
+ -e)
+ shift
+ [ "$#" -gt 0 ] || usage
+ esm_blob="$1"
+ ;;
-s)
shift
[ "$#" -gt 0 ] || usage
@@ -211,9 +218,16 @@ objflags=-S
tmp=$tmpdir/zImage.$$.o
ksection=.kernel:vmlinux.strip
isection=.kernel:initrd
+esection=.kernel:esm_blob
link_address='0x400000'
make_space=y
+
+if [ -n "$esm_blob" -a "$platform" != "pseries" ]; then
+ echo "ESM blob not support on non-pseries platforms" >&2
+ exit 1
+fi
+
case "$platform" in
of)
platformo="$object/of.o $object/epapr.o"
@@ -463,6 +477,10 @@ if [ -n "$dtb" ]; then
fi
fi
+if [ -n "$esm_blob" ]; then
+ addsec $tmp "$esm_blob" $esection
+fi
+
if [ "$platform" != "miboot" ]; then
if [ -n "$link_address" ] ; then
text_start="-Ttext $link_address"
diff --git a/arch/powerpc/boot/zImage.lds.S b/arch/powerpc/boot/zImage.lds.S
index 4ac1e36edfe7..a21f3a76e06f 100644
--- a/arch/powerpc/boot/zImage.lds.S
+++ b/arch/powerpc/boot/zImage.lds.S
@@ -68,6 +68,14 @@ SECTIONS
_initrd_end = .;
}
+ . = ALIGN(4096);
+ .kernel:esm_blob :
+ {
+ _esm_blob_start = .;
+ *(.kernel:esm_blob)
+ _esm_blob_end = .;
+ }
+
#ifdef CONFIG_PPC64_BOOT_WRAPPER
. = ALIGN(256);
.got :
--
2.17.0
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2018-05-31 4:34 [RFC PATCH] powerpc: Add support for adding an ESM blob to the zImage wrapper Benjamin Herrenschmidt
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