[PATCH v7 09/12] powerpc/fsl_booke/kaslr: support nokaslr cmdline parameter

[Jason Yan <yanaijie@huawei.com>]

One may want to disable kaslr when boot, so provide a cmdline parameter
'nokaslr' to support this.

Signed-off-by: Jason Yan <yanaijie@huawei.com>
Cc: Diana Craciun <diana.craciun@nxp.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Reviewed-by: Diana Craciun <diana.craciun@nxp.com>
Tested-by: Diana Craciun <diana.craciun@nxp.com>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/mm/nohash/kaslr_booke.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/powerpc/mm/nohash/kaslr_booke.c b/arch/powerpc/mm/nohash/kaslr_booke.c
index aa1b60c782e7..4a75f2d9bf0e 100644
--- a/arch/powerpc/mm/nohash/kaslr_booke.c
+++ b/arch/powerpc/mm/nohash/kaslr_booke.c
@@ -281,6 +281,11 @@ static unsigned long __init kaslr_legal_offset(void *dt_ptr, unsigned long index
 	return koffset;
 }
 
+static inline __init bool kaslr_disabled(void)
+{
+	return strstr(boot_command_line, "nokaslr") != NULL;
+}
+
 static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size,
 						  unsigned long kernel_sz)
 {
@@ -290,6 +295,8 @@ static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size
 	unsigned long index;
 
 	kaslr_get_cmdline(dt_ptr);
+	if (kaslr_disabled())
+		return 0;
 
 	random = get_boot_seed(dt_ptr);
 
-- 
2.17.2