powerpc: Handle error in mark_rodata_ro() and mark_initmem_nx()

mark_rodata_ro() and mark_initmem_nx() use functions that can
fail like set_memory_nx() and set_memory_ro(), leading to a not
protected kernel.

In case of failure, panic.

Link: https://github.com/KSPP/linux/issues/7
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/b16329611deb89e1af505d43f0e2a91310584d26.1710587887.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c
index 5445587bfe8418a5ea40cbde0c525d3c462eab4a..100f999871bc3be6c56e2ca53ff58f54c2909234 100644 (file)
--- a/arch/powerpc/mm/book3s32/mmu.c
+++ b/arch/powerpc/mm/book3s32/mmu.c
@@ -193,7 +193,7 @@ static bool is_module_segment(unsigned long addr)
        return true;
 }
 
-void mmu_mark_initmem_nx(void)
+int mmu_mark_initmem_nx(void)
 {
        int nb = mmu_has_feature(MMU_FTR_USE_HIGH_BATS) ? 8 : 4;
        int i;
@@ -230,9 +230,10 @@ void mmu_mark_initmem_nx(void)
 
                mtsr(mfsr(i << 28) | 0x10000000, i << 28);
        }
+       return 0;
 }
 
-void mmu_mark_rodata_ro(void)
+int mmu_mark_rodata_ro(void)
 {
        int nb = mmu_has_feature(MMU_FTR_USE_HIGH_BATS) ? 8 : 4;
        int i;
@@ -245,6 +246,8 @@ void mmu_mark_rodata_ro(void)
        }
 
        update_bats();
+
+       return 0;
 }
 
 /*

diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
index 8e84bc214d133c0b29cae908e048747cd5b2993b..6949c2c937e72f0a537ce2a46e78a8fe09c35e55 100644 (file)
--- a/arch/powerpc/mm/mmu_decl.h
+++ b/arch/powerpc/mm/mmu_decl.h
@@ -160,11 +160,11 @@ static inline unsigned long p_block_mapped(phys_addr_t pa) { return 0; }
 #endif
 
 #if defined(CONFIG_PPC_BOOK3S_32) || defined(CONFIG_PPC_8xx) || defined(CONFIG_PPC_E500)
-void mmu_mark_initmem_nx(void);
-void mmu_mark_rodata_ro(void);
+int mmu_mark_initmem_nx(void);
+int mmu_mark_rodata_ro(void);
 #else
-static inline void mmu_mark_initmem_nx(void) { }
-static inline void mmu_mark_rodata_ro(void) { }
+static inline int mmu_mark_initmem_nx(void) { return 0; }
+static inline int mmu_mark_rodata_ro(void) { return 0; }
 #endif
 
 #ifdef CONFIG_PPC_8xx

diff --git a/arch/powerpc/mm/nohash/8xx.c b/arch/powerpc/mm/nohash/8xx.c
index 6be6421086ed990b35428742b3c26f03ecde5668..43d4842bb1c7a787d11dfec71d4c3814592ae99d 100644 (file)
--- a/arch/powerpc/mm/nohash/8xx.c
+++ b/arch/powerpc/mm/nohash/8xx.c
@@ -119,23 +119,26 @@ void __init mmu_mapin_immr(void)
                                    PAGE_KERNEL_NCG, MMU_PAGE_512K, true);
 }
 
-static void mmu_mapin_ram_chunk(unsigned long offset, unsigned long top,
-                               pgprot_t prot, bool new)
+static int mmu_mapin_ram_chunk(unsigned long offset, unsigned long top,
+                              pgprot_t prot, bool new)
 {
        unsigned long v = PAGE_OFFSET + offset;
        unsigned long p = offset;
+       int err = 0;
 
        WARN_ON(!IS_ALIGNED(offset, SZ_512K) || !IS_ALIGNED(top, SZ_512K));
 
-       for (; p < ALIGN(p, SZ_8M) && p < top; p += SZ_512K, v += SZ_512K)
-               __early_map_kernel_hugepage(v, p, prot, MMU_PAGE_512K, new);
-       for (; p < ALIGN_DOWN(top, SZ_8M) && p < top; p += SZ_8M, v += SZ_8M)
-               __early_map_kernel_hugepage(v, p, prot, MMU_PAGE_8M, new);
-       for (; p < ALIGN_DOWN(top, SZ_512K) && p < top; p += SZ_512K, v += SZ_512K)
-               __early_map_kernel_hugepage(v, p, prot, MMU_PAGE_512K, new);
+       for (; p < ALIGN(p, SZ_8M) && p < top && !err; p += SZ_512K, v += SZ_512K)
+               err = __early_map_kernel_hugepage(v, p, prot, MMU_PAGE_512K, new);
+       for (; p < ALIGN_DOWN(top, SZ_8M) && p < top && !err; p += SZ_8M, v += SZ_8M)
+               err = __early_map_kernel_hugepage(v, p, prot, MMU_PAGE_8M, new);
+       for (; p < ALIGN_DOWN(top, SZ_512K) && p < top && !err; p += SZ_512K, v += SZ_512K)
+               err = __early_map_kernel_hugepage(v, p, prot, MMU_PAGE_512K, new);
 
        if (!new)
                flush_tlb_kernel_range(PAGE_OFFSET + v, PAGE_OFFSET + top);
+
+       return err;
 }
 
 unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
@@ -166,27 +169,33 @@ unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
        return top;
 }
 
-void mmu_mark_initmem_nx(void)
+int mmu_mark_initmem_nx(void)
 {
        unsigned long etext8 = ALIGN(__pa(_etext), SZ_8M);
        unsigned long sinittext = __pa(_sinittext);
        unsigned long boundary = strict_kernel_rwx_enabled() ? sinittext : etext8;
        unsigned long einittext8 = ALIGN(__pa(_einittext), SZ_8M);
+       int err = 0;
 
        if (!debug_pagealloc_enabled_or_kfence())
-               mmu_mapin_ram_chunk(boundary, einittext8, PAGE_KERNEL, false);
+               err = mmu_mapin_ram_chunk(boundary, einittext8, PAGE_KERNEL, false);
 
        mmu_pin_tlb(block_mapped_ram, false);
+
+       return err;
 }
 
 #ifdef CONFIG_STRICT_KERNEL_RWX
-void mmu_mark_rodata_ro(void)
+int mmu_mark_rodata_ro(void)
 {
        unsigned long sinittext = __pa(_sinittext);
+       int err;
 
-       mmu_mapin_ram_chunk(0, sinittext, PAGE_KERNEL_ROX, false);
+       err = mmu_mapin_ram_chunk(0, sinittext, PAGE_KERNEL_ROX, false);
        if (IS_ENABLED(CONFIG_PIN_TLB_DATA))
                mmu_pin_tlb(block_mapped_ram, true);
+
+       return err;
 }
 #endif
 

diff --git a/arch/powerpc/mm/nohash/e500.c b/arch/powerpc/mm/nohash/e500.c
index 921c3521ec113e1d99f79230b857d18bf8eb0d9a..266fb22131fc1e0e6c60e2eb95dbaa18e6badbcd 100644 (file)
--- a/arch/powerpc/mm/nohash/e500.c
+++ b/arch/powerpc/mm/nohash/e500.c
@@ -285,19 +285,23 @@ void __init adjust_total_lowmem(void)
 }
 
 #ifdef CONFIG_STRICT_KERNEL_RWX
-void mmu_mark_rodata_ro(void)
+int mmu_mark_rodata_ro(void)
 {
        unsigned long remapped;
 
        remapped = map_mem_in_cams(__max_low_memory, CONFIG_LOWMEM_CAM_NUM, false, false);
 
-       WARN_ON(__max_low_memory != remapped);
+       if (WARN_ON(__max_low_memory != remapped))
+               return -EINVAL;
+
+       return 0;
 }
 #endif
 
-void mmu_mark_initmem_nx(void)
+int mmu_mark_initmem_nx(void)
 {
        /* Everything is done in mmu_mark_rodata_ro() */
+       return 0;
 }
 
 void setup_initial_memory_limit(phys_addr_t first_memblock_base,

diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index face94977cb2fb406711b03b15486d6b64b90a46..cfd622ebf774b01971e8695ed6e997e794b96ea5 100644 (file)
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -130,31 +130,41 @@ void __init mapin_ram(void)
        }
 }
 
-void mark_initmem_nx(void)
+static int __mark_initmem_nx(void)
 {
        unsigned long numpages = PFN_UP((unsigned long)_einittext) -
                                 PFN_DOWN((unsigned long)_sinittext);
+       int err;
 
-       mmu_mark_initmem_nx();
+       err = mmu_mark_initmem_nx();
 
        if (!v_block_mapped((unsigned long)_sinittext)) {
-               set_memory_nx((unsigned long)_sinittext, numpages);
-               set_memory_rw((unsigned long)_sinittext, numpages);
+               err = set_memory_nx((unsigned long)_sinittext, numpages);
+               if (err)
+                       return err;
+               err = set_memory_rw((unsigned long)_sinittext, numpages);
        }
+       return err;
+}
+
+void mark_initmem_nx(void)
+{
+       int err = __mark_initmem_nx();
+
+       if (err)
+               panic("%s() failed, err = %d\n", __func__, err);
 }
 
 #ifdef CONFIG_STRICT_KERNEL_RWX
-void mark_rodata_ro(void)
+static int __mark_rodata_ro(void)
 {
        unsigned long numpages;
 
        if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX) && mmu_has_feature(MMU_FTR_HPTE_TABLE))
                pr_warn("This platform has HASH MMU, STRICT_MODULE_RWX won't work\n");
 
-       if (v_block_mapped((unsigned long)_stext + 1)) {
-               mmu_mark_rodata_ro();
-               return;
-       }
+       if (v_block_mapped((unsigned long)_stext + 1))
+               return mmu_mark_rodata_ro();
 
        /*
         * mark text and rodata as read only. __end_rodata is set by
@@ -164,6 +174,14 @@ void mark_rodata_ro(void)
        numpages = PFN_UP((unsigned long)__end_rodata) -
                   PFN_DOWN((unsigned long)_stext);
 
-       set_memory_ro((unsigned long)_stext, numpages);
+       return set_memory_ro((unsigned long)_stext, numpages);
+}
+
+void mark_rodata_ro(void)
+{
+       int err = __mark_rodata_ro();
+
+       if (err)
+               panic("%s() failed, err = %d\n", __func__, err);
 }
 #endif