From: Hari Bathini <hbathini@linux.ibm.com>
Date: Wed, 14 Jul 2021 12:47:58 +0000 (+0530)
Subject: powerpc/kexec: blacklist functions called in real mode for kprobe
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=8119cefd9a29b71997e62b762932d23499ba4896;p=linux.git

powerpc/kexec: blacklist functions called in real mode for kprobe

As kprobe does not handle events happening in real mode, blacklist the
functions that only get called in real mode or in kexec sequence with
MMU turned off.

Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/162626687834.155313.4692863392927831843.stgit@hbathini-workstation.ibm.com
---

diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index 79930b0bc781a..f17ae20837337 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -712,6 +712,8 @@ _GLOBAL(copy_and_flush)
 	isync
 	blr
 
+_ASM_NOKPROBE_SYMBOL(copy_and_flush); /* Called in real mode */
+
 .align 8
 copy_to_here:
 
diff --git a/arch/powerpc/kexec/core_64.c b/arch/powerpc/kexec/core_64.c
index 8a449b2d8715d..84618d3c8013b 100644
--- a/arch/powerpc/kexec/core_64.c
+++ b/arch/powerpc/kexec/core_64.c
@@ -72,7 +72,8 @@ int default_machine_kexec_prepare(struct kimage *image)
 	return 0;
 }
 
-static void copy_segments(unsigned long ind)
+/* Called during kexec sequence with MMU off */
+static notrace void copy_segments(unsigned long ind)
 {
 	unsigned long entry;
 	unsigned long *ptr;
@@ -105,7 +106,8 @@ static void copy_segments(unsigned long ind)
 	}
 }
 
-void kexec_copy_flush(struct kimage *image)
+/* Called during kexec sequence with MMU off */
+notrace void kexec_copy_flush(struct kimage *image)
 {
 	long i, nr_segments = image->nr_segments;
 	struct  kexec_segment ranges[KEXEC_SEGMENT_MAX];
diff --git a/arch/powerpc/mm/book3s64/hash_native.c b/arch/powerpc/mm/book3s64/hash_native.c
index 52e170bd95ae1..d8279bfe68ea9 100644
--- a/arch/powerpc/mm/book3s64/hash_native.c
+++ b/arch/powerpc/mm/book3s64/hash_native.c
@@ -787,7 +787,7 @@ static void hpte_decode(struct hash_pte *hpte, unsigned long slot,
  * TODO: add batching support when enabled.  remember, no dynamic memory here,
  * although there is the control page available...
  */
-static void native_hpte_clear(void)
+static notrace void native_hpte_clear(void)
 {
 	unsigned long vpn = 0;
 	unsigned long slot, slots;
diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c
index 9ffa65074cb00..300099de553b8 100644
--- a/arch/powerpc/mm/book3s64/pgtable.c
+++ b/arch/powerpc/mm/book3s64/pgtable.c
@@ -172,8 +172,8 @@ pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
 }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
-/* For use by kexec */
-void mmu_cleanup_all(void)
+/* For use by kexec, called with MMU off */
+notrace void mmu_cleanup_all(void)
 {
 	if (radix_enabled())
 		radix__mmu_cleanup_all();
diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index e50ddf129c15c..ae20add7954a0 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -679,7 +679,8 @@ void radix__early_init_mmu_secondary(void)
 	mtspr(SPRN_UAMOR, 0);
 }
 
-void radix__mmu_cleanup_all(void)
+/* Called during kexec sequence with MMU off */
+notrace void radix__mmu_cleanup_all(void)
 {
 	unsigned long lpcr;
 
diff --git a/arch/powerpc/platforms/ps3/htab.c b/arch/powerpc/platforms/ps3/htab.c
index 7ddc7ec6a7c06..ef710a7159035 100644
--- a/arch/powerpc/platforms/ps3/htab.c
+++ b/arch/powerpc/platforms/ps3/htab.c
@@ -169,7 +169,8 @@ static void ps3_hpte_invalidate(unsigned long slot, unsigned long vpn,
 	spin_unlock_irqrestore(&ps3_htab_lock, flags);
 }
 
-static void ps3_hpte_clear(void)
+/* Called during kexec sequence with MMU off */
+static notrace void ps3_hpte_clear(void)
 {
 	unsigned long hpte_count = (1UL << ppc64_pft_size) >> 4;
 	u64 i;
diff --git a/arch/powerpc/platforms/ps3/mm.c b/arch/powerpc/platforms/ps3/mm.c
index a81eac35d9009..9c44f335c0b94 100644
--- a/arch/powerpc/platforms/ps3/mm.c
+++ b/arch/powerpc/platforms/ps3/mm.c
@@ -195,9 +195,11 @@ fail:
 
 /**
  * ps3_mm_vas_destroy -
+ *
+ * called during kexec sequence with MMU off.
  */
 
-void ps3_mm_vas_destroy(void)
+notrace void ps3_mm_vas_destroy(void)
 {
 	int result;
 
@@ -1243,9 +1245,11 @@ void __init ps3_mm_init(void)
 
 /**
  * ps3_mm_shutdown - final cleanup of address space
+ *
+ * called during kexec sequence with MMU off.
  */
 
-void ps3_mm_shutdown(void)
+notrace void ps3_mm_shutdown(void)
 {
 	ps3_mm_region_destroy(&map.r1);
 }
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index dab356e3ff87c..869ef638698ab 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -801,7 +801,8 @@ static long pSeries_lpar_hpte_remove(unsigned long hpte_group)
 	return -1;
 }
 
-static void manual_hpte_clear_all(void)
+/* Called during kexec sequence with MMU off */
+static notrace void manual_hpte_clear_all(void)
 {
 	unsigned long size_bytes = 1UL << ppc64_pft_size;
 	unsigned long hpte_count = size_bytes >> 4;
@@ -834,7 +835,8 @@ static void manual_hpte_clear_all(void)
 	}
 }
 
-static int hcall_hpte_clear_all(void)
+/* Called during kexec sequence with MMU off */
+static notrace int hcall_hpte_clear_all(void)
 {
 	int rc;
 
@@ -845,7 +847,8 @@ static int hcall_hpte_clear_all(void)
 	return rc;
 }
 
-static void pseries_hpte_clear_all(void)
+/* Called during kexec sequence with MMU off */
+static notrace void pseries_hpte_clear_all(void)
 {
 	int rc;