From 0b2859a74306b2b89f6e77c216fe0992ff890fa6 Mon Sep 17 00:00:00 2001
From: Christophe Leroy <christophe.leroy@csgroup.eu>
Date: Fri, 15 Oct 2021 12:02:47 +0200
Subject: [PATCH] powerpc/fsl_booke: Allocate separate TLBCAMs for readonly
memory
Reorganise TLBCAM allocation so that when STRICT_KERNEL_RWX is
enabled, TLBCAMs are allocated such that readonly memory uses
different TLBCAMs.
This results in an allocation looking like:
Memory CAM mapping: 4/4/4/1/1/1/1/16/16/16/64/64/64/256/256 Mb, residual: 256Mb
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8ca169bc288261a0e0558712f979023c3a960ebb.1634292136.git.christophe.leroy@csgroup.eu
---
arch/powerpc/mm/nohash/fsl_book3e.c | 25 ++++++++++++++++++++++---
1 file changed, 22 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/mm/nohash/fsl_book3e.c b/arch/powerpc/mm/nohash/fsl_book3e.c
index 375b2b8238c16..c1bc11f46344f 100644
--- a/arch/powerpc/mm/nohash/fsl_book3e.c
+++ b/arch/powerpc/mm/nohash/fsl_book3e.c
@@ -171,15 +171,34 @@ static unsigned long map_mem_in_cams_addr(phys_addr_t phys, unsigned long virt,
{
int i;
unsigned long amount_mapped = 0;
+ unsigned long boundary;
+
+ if (strict_kernel_rwx_enabled())
+ boundary = (unsigned long)(_sinittext - _stext);
+ else
+ boundary = ram;
/* Calculate CAM values */
- for (i = 0; ram && i < max_cam_idx; i++) {
+ for (i = 0; boundary && i < max_cam_idx; i++) {
+ unsigned long cam_sz;
+ pgprot_t prot = PAGE_KERNEL_X;
+
+ cam_sz = calc_cam_sz(boundary, virt, phys);
+ if (!dryrun)
+ settlbcam(i, virt, phys, cam_sz, pgprot_val(prot), 0);
+
+ boundary -= cam_sz;
+ amount_mapped += cam_sz;
+ virt += cam_sz;
+ phys += cam_sz;
+ }
+ for (ram -= amount_mapped; ram && i < max_cam_idx; i++) {
unsigned long cam_sz;
+ pgprot_t prot = PAGE_KERNEL_X;
cam_sz = calc_cam_sz(ram, virt, phys);
if (!dryrun)
- settlbcam(i, virt, phys, cam_sz,
- pgprot_val(PAGE_KERNEL_X), 0);
+ settlbcam(i, virt, phys, cam_sz, pgprot_val(prot), 0);
ram -= cam_sz;
amount_mapped += cam_sz;
--
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