No more map the reserved region with "no-map" property by marking the corresponding TLB entries with invalid entry (=0) to avoid speculative access.
This patch fixes an issue on STM32MP15x where predictive read access on secure DDR area are caught by OP-TEE.
Signed-off-by: Patrick Delaunay patrick.delaunay@st.com ---
arch/arm/include/asm/system.h | 3 +++ arch/arm/lib/cache-cp15.c | 19 +++++++++++++++++-- 2 files changed, 20 insertions(+), 2 deletions(-)
diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h index ce552944b7..932f12af1c 100644 --- a/arch/arm/include/asm/system.h +++ b/arch/arm/include/asm/system.h @@ -458,6 +458,7 @@ static inline void set_dacr(unsigned int val)
/* options available for data cache on each page */ enum dcache_option { + INVALID_ENTRY = 0, DCACHE_OFF = TTB_SECT | TTB_SECT_MAIR(0) | TTB_SECT_XN_MASK, DCACHE_WRITETHROUGH = TTB_SECT | TTB_SECT_MAIR(1), DCACHE_WRITEBACK = TTB_SECT | TTB_SECT_MAIR(2), @@ -488,6 +489,7 @@ enum dcache_option { * 1 1 1 Outer/Inner Write-Back, Read-Allocate Write-Allocate */ enum dcache_option { + INVALID_ENTRY = 0, DCACHE_OFF = TTB_SECT_DOMAIN(0) | TTB_SECT_XN_MASK | TTB_SECT, DCACHE_WRITETHROUGH = DCACHE_OFF | TTB_SECT_C_MASK, DCACHE_WRITEBACK = DCACHE_WRITETHROUGH | TTB_SECT_B_MASK, @@ -497,6 +499,7 @@ enum dcache_option { #define TTB_SECT_AP (3 << 10) /* options available for data cache on each page */ enum dcache_option { + INVALID_ENTRY = 0, DCACHE_OFF = 0x12, DCACHE_WRITETHROUGH = 0x1a, DCACHE_WRITEBACK = 0x1e, diff --git a/arch/arm/lib/cache-cp15.c b/arch/arm/lib/cache-cp15.c index abd81d21c7..9e778dfd06 100644 --- a/arch/arm/lib/cache-cp15.c +++ b/arch/arm/lib/cache-cp15.c @@ -6,6 +6,7 @@
#include <common.h> #include <cpu_func.h> +#include <lmb.h> #include <log.h> #include <asm/system.h> #include <asm/cache.h> @@ -105,18 +106,32 @@ void mmu_set_region_dcache_behaviour(phys_addr_t start, size_t size, __weak void dram_bank_mmu_setup(int bank) { struct bd_info *bd = gd->bd; + struct lmb lmb; int i;
/* bd->bi_dram is available only after relocation */ if ((gd->flags & GD_FLG_RELOC) == 0) return;
+ /* + * don't allow cache on reserved memory tagged 'no-map' in DT + * => avoid speculative access to "secure" data + */ + if (IS_ENABLED(CONFIG_LMB)) + lmb_init_and_reserve(&lmb, bd, (void *)gd->fdt_blob); + debug("%s: bank: %d\n", __func__, bank); for (i = bd->bi_dram[bank].start >> MMU_SECTION_SHIFT; i < (bd->bi_dram[bank].start >> MMU_SECTION_SHIFT) + (bd->bi_dram[bank].size >> MMU_SECTION_SHIFT); - i++) - set_section_dcache(i, DCACHE_DEFAULT_OPTION); + i++) { + if (IS_ENABLED(CONFIG_LMB) && + lmb_is_reserved_flags(&lmb, i << MMU_SECTION_SHIFT, + LMB_NOMAP)) + set_section_dcache(i, INVALID_ENTRY); + else + set_section_dcache(i, DCACHE_DEFAULT_OPTION); + } }
/* to activate the MMU we need to set up virtual memory: use 1M areas */