[PATCH] powerpc/prom_init: Undo relocation before entering secure mode

The ultravisor will do an integrity check of the kernel image but we
relocated it so the check will fail. Restore the original image by
relocating it back to the kernel virtual base address.

This works because during build vmlinux is linked with an expected virtual
runtime address of KERNELBASE.

Fixes: 6a9c930bd775 ("powerpc/prom_init: Add the ESM call to prom_init")
Signed-off-by: Thiago Jung Bauermann <redacted>
---
 arch/powerpc/include/asm/elf.h         |  3 +++
 arch/powerpc/kernel/prom_init.c        | 11 +++++++++++
 arch/powerpc/kernel/prom_init_check.sh |  3 ++-
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/elf.h b/arch/powerpc/include/asm/elf.h
index 409c9bfb43d9..57c229a86f08 100644
--- a/arch/powerpc/include/asm/elf.h
+++ b/arch/powerpc/include/asm/elf.h

@@ -175,4 +175,7 @@ do {									\
 	ARCH_DLINFO_CACHE_GEOMETRY;					\
 } while (0)
 
+/* Relocate the kernel image to @final_address */
+void relocate(unsigned long final_address);
+
 #endif /* _ASM_POWERPC_ELF_H */

diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index 74f70f90eff0..44b1d404250e 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c

@@ -3249,7 +3249,18 @@ static void setup_secure_guest(unsigned long kbase, unsigned long fdt)
 	/* Switch to secure mode. */
 	prom_printf("Switching to secure mode.\n");
 
+	/*
+	 * The ultravisor will do an integrity check of the kernel image but we
+	 * relocated it so the check will fail. Restore the original image by
+	 * relocating it back to the kernel virtual base address.
+	 */
+	relocate(KERNELBASE);
+
 	ret = enter_secure_mode(kbase, fdt);
+
+	/* Relocate the kernel again. */
+	relocate(kbase);
+
 	if (ret != U_SUCCESS) {
 		prom_printf("Returned %d from switching to secure mode.\n", ret);
 		prom_rtas_os_term("Switch to secure mode failed.\n");

diff --git a/arch/powerpc/kernel/prom_init_check.sh b/arch/powerpc/kernel/prom_init_check.sh
index 160bef0d553d..16535ccc0fa0 100644
--- a/arch/powerpc/kernel/prom_init_check.sh
+++ b/arch/powerpc/kernel/prom_init_check.sh

@@ -26,7 +26,8 @@ _end enter_prom $MEM_FUNCS reloc_offset __secondary_hold
 __secondary_hold_acknowledge __secondary_hold_spinloop __start
 logo_linux_clut224 btext_prepare_BAT
 reloc_got2 kernstart_addr memstart_addr linux_banner _stext
-__prom_init_toc_start __prom_init_toc_end btext_setup_display TOC."
+__prom_init_toc_start __prom_init_toc_end btext_setup_display TOC.
+relocate"
 
 NM="$1"
 OBJ="$2"

Thiago Jung Bauermann [off-list ref] writes:

The ultravisor will do an integrity check of the kernel image but we
relocated it so the check will fail. Restore the original image by
relocating it back to the kernel virtual base address.

This works because during build vmlinux is linked with an expected virtual
runtime address of KERNELBASE.

Fixes: 6a9c930bd775 ("powerpc/prom_init: Add the ESM call to prom_init")
Signed-off-by: Thiago Jung Bauermann <redacted>

I meant to put a Suggested-by: Paul Mackerras [off-list ref]

Sorry. Will add it if there's a v2.

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

Thiago Jung Bauermann [off-list ref] writes:

Thiago Jung Bauermann [off-list ref] writes:

quoted

The ultravisor will do an integrity check of the kernel image but we
relocated it so the check will fail. Restore the original image by
relocating it back to the kernel virtual base address.

This works because during build vmlinux is linked with an expected virtual
runtime address of KERNELBASE.

Fixes: 6a9c930bd775 ("powerpc/prom_init: Add the ESM call to prom_init")
Signed-off-by: Thiago Jung Bauermann <redacted>

I meant to put a Suggested-by: Paul Mackerras [off-list ref]

Sorry. Will add it if there's a v2.

Ping?

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

On Wed, Sep 11, 2019 at 01:34:33PM -0300, Thiago Jung Bauermann wrote:

The ultravisor will do an integrity check of the kernel image but we
relocated it so the check will fail. Restore the original image by
relocating it back to the kernel virtual base address.

This works because during build vmlinux is linked with an expected virtual
runtime address of KERNELBASE.

Fixes: 6a9c930bd775 ("powerpc/prom_init: Add the ESM call to prom_init")
Signed-off-by: Thiago Jung Bauermann <redacted>

Tested-by: Ram Pai <redacted>

-- 
Ram Pai

Thiago Jung Bauermann [off-list ref] writes:

The ultravisor will do an integrity check of the kernel image but we
relocated it so the check will fail. Restore the original image by
relocating it back to the kernel virtual base address.

This works because during build vmlinux is linked with an expected virtual
runtime address of KERNELBASE.

Fixes: 6a9c930bd775 ("powerpc/prom_init: Add the ESM call to prom_init")
Signed-off-by: Thiago Jung Bauermann <redacted>
---
 arch/powerpc/include/asm/elf.h         |  3 +++
 arch/powerpc/kernel/prom_init.c        | 11 +++++++++++
 arch/powerpc/kernel/prom_init_check.sh |  3 ++-
 3 files changed, 16 insertions(+), 1 deletion(-)

This breaks the build when CONFIG_RELOCATABLE=n:

    prom_init.c:(.init.text+0x3160): undefined reference to `relocate'

See http://kisskb.ellerman.id.au/kisskb/buildresult/14004234/

cheers

On Wed, 2019-09-11 at 16:34:33 UTC, Thiago Jung Bauermann wrote:

The ultravisor will do an integrity check of the kernel image but we
relocated it so the check will fail. Restore the original image by
relocating it back to the kernel virtual base address.

This works because during build vmlinux is linked with an expected virtual
runtime address of KERNELBASE.

Fixes: 6a9c930bd775 ("powerpc/prom_init: Add the ESM call to prom_init")
Signed-off-by: Thiago Jung Bauermann <redacted>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/05d9a952832cb206a32e3705eff6edebdb2207e7

cheers