Commit b868fff5 authored by Sam Edwards's avatar Sam Edwards Committed by Will Deacon
Browse files

arm64: mm: Represent physical memory with phys_addr_t and resource_size_t 



This is a type-correctness cleanup to MMU/boot code that replaces
several instances of void * and u64 with phys_addr_t (to represent
addresses) and resource_size_t (to represent sizes) to emphasize that
the code in question concerns physical memory specifically.

The rationale for this change is to improve clarity and readability in
a few modules that handle both types (physical and virtual) of address
and differentiation is essential.

I have left u64 in cases where the address may be either physical or
virtual, where the address is exclusively virtual but used in heavy
pointer arithmetic, and in cases I may have overlooked. I do not
necessarily consider u64 the ideal type in those situations, but it
avoids breaking existing semantics in this cleanup.

This patch provably has no effect at runtime: I have verified that
.text of vmlinux is identical after this change.

Signed-off-by: default avatarSam Edwards <CFSworks@gmail.com>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent c56aa9a6

arch/arm64/kernel/pi/map_kernel.c

+13 −13
Original line number Diff line number Diff line
@@ -18,9 +18,9 @@ 


extern const u8 __eh_frame_start[], __eh_frame_end[];



extern void idmap_cpu_replace_ttbr1(void *pgdir);

extern void idmap_cpu_replace_ttbr1(phys_addr_t pgdir);



static void __init map_segment(pgd_t *pg_dir, u64 *pgd, u64 va_offset,

static void __init map_segment(pgd_t *pg_dir, phys_addr_t *pgd, u64 va_offset,

			       void *start, void *end, pgprot_t prot,

			       bool may_use_cont, int root_level)

{
@@ -40,7 +40,7 @@ static void __init map_kernel(u64 kaslr_offset, u64 va_offset, int root_level) 
{

	bool enable_scs = IS_ENABLED(CONFIG_UNWIND_PATCH_PAC_INTO_SCS);

	bool twopass = IS_ENABLED(CONFIG_RELOCATABLE);

	u64 pgdp = (u64)init_pg_dir + PAGE_SIZE;

	phys_addr_t pgdp = (phys_addr_t)init_pg_dir + PAGE_SIZE;

	pgprot_t text_prot = PAGE_KERNEL_ROX;

	pgprot_t data_prot = PAGE_KERNEL;

	pgprot_t prot;
@@ -90,7 +90,7 @@ static void __init map_kernel(u64 kaslr_offset, u64 va_offset, int root_level) 
		    true, root_level);

	dsb(ishst);



	idmap_cpu_replace_ttbr1(init_pg_dir);

	idmap_cpu_replace_ttbr1((phys_addr_t)init_pg_dir);



	if (twopass) {

		if (IS_ENABLED(CONFIG_RELOCATABLE))
@@ -129,10 +129,10 @@ static void __init map_kernel(u64 kaslr_offset, u64 va_offset, int root_level) 
	/* Copy the root page table to its final location */

	memcpy((void *)swapper_pg_dir + va_offset, init_pg_dir, PAGE_SIZE);

	dsb(ishst);

	idmap_cpu_replace_ttbr1(swapper_pg_dir);

	idmap_cpu_replace_ttbr1((phys_addr_t)swapper_pg_dir);

}



static void noinline __section(".idmap.text") set_ttbr0_for_lpa2(u64 ttbr)

static void noinline __section(".idmap.text") set_ttbr0_for_lpa2(phys_addr_t ttbr)

{

	u64 sctlr = read_sysreg(sctlr_el1);

	u64 tcr = read_sysreg(tcr_el1) | TCR_DS;
@@ -172,7 +172,7 @@ static void __init remap_idmap_for_lpa2(void) 
	 */

	create_init_idmap(init_pg_dir, mask);

	dsb(ishst);

	set_ttbr0_for_lpa2((u64)init_pg_dir);

	set_ttbr0_for_lpa2((phys_addr_t)init_pg_dir);



	/*

	 * Recreate the initial ID map with the same granularity as before.
@@ -185,17 +185,17 @@ static void __init remap_idmap_for_lpa2(void) 
	dsb(ishst);



	/* switch back to the updated initial ID map */

	set_ttbr0_for_lpa2((u64)init_idmap_pg_dir);

	set_ttbr0_for_lpa2((phys_addr_t)init_idmap_pg_dir);



	/* wipe the temporary ID map from memory */

	memset(init_pg_dir, 0, (char *)init_pg_end - (char *)init_pg_dir);

}



static void *__init map_fdt(u64 fdt)

static void *__init map_fdt(phys_addr_t fdt)

{

	static u8 ptes[INIT_IDMAP_FDT_SIZE] __initdata __aligned(PAGE_SIZE);

	u64 efdt = fdt + MAX_FDT_SIZE;

	u64 ptep = (u64)ptes;

	phys_addr_t efdt = fdt + MAX_FDT_SIZE;

	phys_addr_t ptep = (phys_addr_t)ptes; /* We're idmapped when called */



	/*

	 * Map up to MAX_FDT_SIZE bytes, but avoid overlap with
@@ -232,7 +232,7 @@ static bool __init ng_mappings_allowed(void) 
	return true;

}



asmlinkage void __init early_map_kernel(u64 boot_status, void *fdt)

asmlinkage void __init early_map_kernel(u64 boot_status, phys_addr_t fdt)

{

	static char const chosen_str[] __initconst = "/chosen";

	u64 va_base, pa_base = (u64)&_text;
@@ -240,7 +240,7 @@ asmlinkage void __init early_map_kernel(u64 boot_status, void *fdt) 
	int root_level = 4 - CONFIG_PGTABLE_LEVELS;

	int va_bits = VA_BITS;

	int chosen;

	void *fdt_mapped = map_fdt((u64)fdt);

	void *fdt_mapped = map_fdt(fdt);



	/* Clear BSS and the initial page tables */

	memset(__bss_start, 0, (char *)init_pg_end - (char *)__bss_start);

arch/arm64/kernel/pi/map_range.c

+12 −8
Original line number Diff line number Diff line
@@ -26,8 +26,9 @@ 
 * @va_offset:		Offset between a physical page and its current mapping

 * 			in the VA space

 */

void __init map_range(u64 *pte, u64 start, u64 end, u64 pa, pgprot_t prot,

		      int level, pte_t *tbl, bool may_use_cont, u64 va_offset)

void __init map_range(phys_addr_t *pte, u64 start, u64 end, phys_addr_t pa,

		      pgprot_t prot, int level, pte_t *tbl, bool may_use_cont,

		      u64 va_offset)

{

	u64 cmask = (level == 3) ? CONT_PTE_SIZE - 1 : U64_MAX;

	ptdesc_t protval = pgprot_val(prot) & ~PTE_TYPE_MASK;
@@ -87,19 +88,22 @@ void __init map_range(u64 *pte, u64 start, u64 end, u64 pa, pgprot_t prot, 
	}

}



asmlinkage u64 __init create_init_idmap(pgd_t *pg_dir, ptdesc_t clrmask)

asmlinkage phys_addr_t __init create_init_idmap(pgd_t *pg_dir, ptdesc_t clrmask)

{

	u64 ptep = (u64)pg_dir + PAGE_SIZE;

	phys_addr_t ptep = (phys_addr_t)pg_dir + PAGE_SIZE; /* MMU is off */

	pgprot_t text_prot = PAGE_KERNEL_ROX;

	pgprot_t data_prot = PAGE_KERNEL;



	pgprot_val(text_prot) &= ~clrmask;

	pgprot_val(data_prot) &= ~clrmask;



	map_range(&ptep, (u64)_stext, (u64)__initdata_begin, (u64)_stext,

		  text_prot, IDMAP_ROOT_LEVEL, (pte_t *)pg_dir, false, 0);

	map_range(&ptep, (u64)__initdata_begin, (u64)_end, (u64)__initdata_begin,

		  data_prot, IDMAP_ROOT_LEVEL, (pte_t *)pg_dir, false, 0);

	/* MMU is off; pointer casts to phys_addr_t are safe */

	map_range(&ptep, (u64)_stext, (u64)__initdata_begin,

		  (phys_addr_t)_stext, text_prot, IDMAP_ROOT_LEVEL,

		  (pte_t *)pg_dir, false, 0);

	map_range(&ptep, (u64)__initdata_begin, (u64)_end,

		  (phys_addr_t)__initdata_begin, data_prot, IDMAP_ROOT_LEVEL,

		  (pte_t *)pg_dir, false, 0);



	return ptep;

}

arch/arm64/kernel/pi/pi.h

+5 −4
Original line number Diff line number Diff line
@@ -29,9 +29,10 @@ u64 kaslr_early_init(void *fdt, int chosen); 
void relocate_kernel(u64 offset);

int scs_patch(const u8 eh_frame[], int size);



void map_range(u64 *pgd, u64 start, u64 end, u64 pa, pgprot_t prot,

	       int level, pte_t *tbl, bool may_use_cont, u64 va_offset);

void map_range(phys_addr_t *pte, u64 start, u64 end, phys_addr_t pa,

	       pgprot_t prot, int level, pte_t *tbl, bool may_use_cont,

	       u64 va_offset);



asmlinkage void early_map_kernel(u64 boot_status, void *fdt);

asmlinkage void early_map_kernel(u64 boot_status, phys_addr_t fdt);



asmlinkage u64 create_init_idmap(pgd_t *pgd, ptdesc_t clrmask);
 
asmlinkage phys_addr_t create_init_idmap(pgd_t *pgd, ptdesc_t clrmask);

arch/arm64/mm/init.c

+3 −3
Original line number Diff line number Diff line
@@ -243,7 +243,7 @@ void __init arm64_memblock_init(void) 
	 */

	if (memory_limit != PHYS_ADDR_MAX) {

		memblock_mem_limit_remove_map(memory_limit);

		memblock_add(__pa_symbol(_text), (u64)(_end - _text));

		memblock_add(__pa_symbol(_text), (resource_size_t)(_end - _text));

	}



	if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) {
@@ -252,8 +252,8 @@ void __init arm64_memblock_init(void) 
		 * initrd to become inaccessible via the linear mapping.

		 * Otherwise, this is a no-op

		 */

		u64 base = phys_initrd_start & PAGE_MASK;

		u64 size = PAGE_ALIGN(phys_initrd_start + phys_initrd_size) - base;

		phys_addr_t base = phys_initrd_start & PAGE_MASK;

		resource_size_t size = PAGE_ALIGN(phys_initrd_start + phys_initrd_size) - base;



		/*

		 * We can only add back the initrd memory if we don't end up

arch/arm64/mm/mmu.c

+9 −8
Original line number Diff line number Diff line
@@ -794,17 +794,18 @@ static void __init declare_kernel_vmas(void) 
	declare_vma(&vmlinux_seg[4], _data, _end, 0);

}



void __pi_map_range(u64 *pgd, u64 start, u64 end, u64 pa, pgprot_t prot,

		    int level, pte_t *tbl, bool may_use_cont, u64 va_offset);

void __pi_map_range(phys_addr_t *pte, u64 start, u64 end, phys_addr_t pa,

		    pgprot_t prot, int level, pte_t *tbl, bool may_use_cont,

		    u64 va_offset);



static u8 idmap_ptes[IDMAP_LEVELS - 1][PAGE_SIZE] __aligned(PAGE_SIZE) __ro_after_init,

	  kpti_ptes[IDMAP_LEVELS - 1][PAGE_SIZE] __aligned(PAGE_SIZE) __ro_after_init;



static void __init create_idmap(void)

{

	u64 start = __pa_symbol(__idmap_text_start);

	u64 end   = __pa_symbol(__idmap_text_end);

	u64 ptep  = __pa_symbol(idmap_ptes);

	phys_addr_t start = __pa_symbol(__idmap_text_start);

	phys_addr_t end   = __pa_symbol(__idmap_text_end);

	phys_addr_t ptep  = __pa_symbol(idmap_ptes);



	__pi_map_range(&ptep, start, end, start, PAGE_KERNEL_ROX,

		       IDMAP_ROOT_LEVEL, (pte_t *)idmap_pg_dir, false,
@@ -812,7 +813,7 @@ static void __init create_idmap(void) 


	if (IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0) && !arm64_use_ng_mappings) {

		extern u32 __idmap_kpti_flag;

		u64 pa = __pa_symbol(&__idmap_kpti_flag);

		phys_addr_t pa = __pa_symbol(&__idmap_kpti_flag);



		/*

		 * The KPTI G-to-nG conversion code needs a read-write mapping
@@ -1331,8 +1332,8 @@ static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size) 
struct range arch_get_mappable_range(void)

{

	struct range mhp_range;

	u64 start_linear_pa = __pa(_PAGE_OFFSET(vabits_actual));

	u64 end_linear_pa = __pa(PAGE_END - 1);

	phys_addr_t start_linear_pa = __pa(_PAGE_OFFSET(vabits_actual));

	phys_addr_t end_linear_pa = __pa(PAGE_END - 1);



	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {

		/*