* [PATCH] powerpc/64: Fix booting large kernels with STRICT_KERNEL_RWX
@ 2019-03-27 3:35 Russell Currey
2019-04-21 14:18 ` Michael Ellerman
0 siblings, 1 reply; 2+ messages in thread
From: Russell Currey @ 2019-03-27 3:35 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Russell Currey
With STRICT_KERNEL_RWX enabled anything marked __init is placed at a 16M
boundary. This is necessary so that it can be repurposed later with
different permissions. However, in kernels with text larger than 16M,
this pushes early_setup past 32M, incapable of being reached by the
branch instruction.
Fix this by setting the CTR and branching there instead.
Fixes: 1e0fc9d1eb2b ("powerpc/Kconfig: Enable STRICT_KERNEL_RWX for some configs")
Signed-off-by: Russell Currey <ruscur@russell.cc>
---
arch/powerpc/kernel/head_64.S | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index 3fad8d499767..c2b53febadd9 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -968,7 +968,9 @@ start_here_multiplatform:
/* Restore parameters passed from prom_init/kexec */
mr r3,r31
- bl early_setup /* also sets r13 and SPRG_PACA */
+ LOAD_REG_ADDR(r12, early_setup)
+ mtctr r12
+ bctrl /* also sets r13 and SPRG_PACA */
LOAD_REG_ADDR(r3, start_here_common)
ld r4,PACAKMSR(r13)
--
2.21.0
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2019-03-27 3:35 [PATCH] powerpc/64: Fix booting large kernels with STRICT_KERNEL_RWX Russell Currey
2019-04-21 14:18 ` Michael Ellerman
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