x86-32, hibernate: Set up temporary text mapping for 32bit system

Set up the temporary text mapping for the final jump address
so that the system could jump to the right address after all
the pages have been copied back to their original address -
otherwise the final mapping for the jump address is invalid.

Analogous changes were made for 64-bit in commit 65c0554b73c9
(x86/power/64: Fix kernel text mapping corruption during image
restoration).

Signed-off-by: Zhimin Gu <[e-mail]>
Acked-by: Pavel Machek <[e-mail]>
Signed-off-by: Chen Yu <[e-mail]>
Acked-by: Thomas Gleixner <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

arch/x86/power/hibernate.c

···
 	if (max_size < sizeof(struct restore_data_record))
 		return -EOVERFLOW;
 	rdr->magic = RESTORE_MAGIC;
-#ifdef CONFIG_X86_64
 	rdr->jump_address = (unsigned long)restore_registers;
 	rdr->jump_address_phys = __pa_symbol(restore_registers);
-#endif
 
 	/*
 	 * The restore code fixes up CR3 and CR4 in the following sequence:
···
 		return -EINVAL;
 	}
 
-#ifdef CONFIG_X86_64
 	restore_jump_address = rdr->jump_address;
 	jump_address_phys = rdr->jump_address_phys;
-#endif
 	restore_cr3 = rdr->cr3;
 
 	if (hibernation_e820_mismatch(rdr->e820_digest)) {

arch/x86/power/hibernate_32.c

···
 #endif
 }
 
+static int set_up_temporary_text_mapping(pgd_t *pgd_base)
+{
+	pgd_t *pgd;
+	pmd_t *pmd;
+	pte_t *pte;
+
+	pgd = pgd_base + pgd_index(restore_jump_address);
+
+	pmd = resume_one_md_table_init(pgd);
+	if (!pmd)
+		return -ENOMEM;
+
+	if (boot_cpu_has(X86_FEATURE_PSE)) {
+		set_pmd(pmd + pmd_index(restore_jump_address),
+		__pmd((jump_address_phys & PMD_MASK) | pgprot_val(PAGE_KERNEL_LARGE_EXEC)));
+	} else {
+		pte = resume_one_page_table_init(pmd);
+		if (!pte)
+			return -ENOMEM;
+		set_pte(pte + pte_index(restore_jump_address),
+		__pte((jump_address_phys & PAGE_MASK) | pgprot_val(PAGE_KERNEL_EXEC)));
+	}
+
+	return 0;
+}
+
 asmlinkage int swsusp_arch_resume(void)
 {
 	int error;
···
 		return -ENOMEM;
 
 	resume_init_first_level_page_table(resume_pg_dir);
+
+	error = set_up_temporary_text_mapping(resume_pg_dir);
+	if (error)
+		return error;
+
 	error = resume_physical_mapping_init(resume_pg_dir);
 	if (error)
 		return error;

arch/x86/power/hibernate_asm_32.S

···
 ENDPROC(swsusp_arch_suspend)
 
 ENTRY(restore_image)
+	/* prepare to jump to the image kernel */
+	movl	restore_jump_address, %ebx
 	movl	restore_cr3, %ebp
 
 	movl	mmu_cr4_features, %ecx
···
 	.p2align 4,,7
 
 done:
+	jmpl	*%ebx
 
 	/* code below belongs to the image kernel */
 	.align PAGE_SIZE