powerpc/vdso: Replace vdso_base by vdso

All other architectures but s390 use a void pointer named 'vdso'
to reference the VDSO mapping.

In a following patch, the VDSO data page will be put in front of
text, vdso_base will then not anymore point to VDSO text.

To avoid confusion between vdso_base and VDSO text, rename vdso_base
into vdso and make it a void __user *.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8e6cefe474aa4ceba028abb729485cd46c140990.1601197618.git.christophe.leroy@csgroup.eu

arch/powerpc/include/asm/book3s/32/mmu-hash.h

@@ -90,7 +90,7 @@ struct hash_pte {
 
 typedef struct {
 	unsigned long id;
-	unsigned long vdso_base;
+	void __user *vdso;
 } mm_context_t;
 
 void update_bats(void);

arch/powerpc/include/asm/book3s/64/mmu.h

@@ -111,7 +111,7 @@ typedef struct {
 
 	struct hash_mm_context *hash_context;
 
-	unsigned long vdso_base;
+	void __user *vdso;
 	/*
 	 * pagetable fragment support
 	 */

arch/powerpc/include/asm/elf.h

@@ -169,7 +169,7 @@ do {									\
 	NEW_AUX_ENT(AT_DCACHEBSIZE, dcache_bsize);			\
 	NEW_AUX_ENT(AT_ICACHEBSIZE, icache_bsize);			\
 	NEW_AUX_ENT(AT_UCACHEBSIZE, ucache_bsize);			\
-	VDSO_AUX_ENT(AT_SYSINFO_EHDR, current->mm->context.vdso_base);	\
+	VDSO_AUX_ENT(AT_SYSINFO_EHDR, (unsigned long)current->mm->context.vdso);\
 	ARCH_DLINFO_CACHE_GEOMETRY;					\
 } while (0)
 

arch/powerpc/include/asm/mmu_context.h

@@ -262,8 +262,10 @@ extern void arch_exit_mmap(struct mm_struct *mm);
 static inline void arch_unmap(struct mm_struct *mm,
 			      unsigned long start, unsigned long end)
 {
-	if (start <= mm->context.vdso_base && mm->context.vdso_base < end)
-		mm->context.vdso_base = 0;
+	unsigned long vdso_base = (unsigned long)mm->context.vdso;
+
+	if (start <= vdso_base && vdso_base < end)
+		mm->context.vdso = NULL;
 }
 
 #ifdef CONFIG_PPC_MEM_KEYS

arch/powerpc/include/asm/nohash/32/mmu-40x.h

@@ -57,7 +57,7 @@
 typedef struct {
 	unsigned int	id;
 	unsigned int	active;
-	unsigned long	vdso_base;
+	void __user	*vdso;
 } mm_context_t;
 
 #endif /* !__ASSEMBLY__ */

arch/powerpc/include/asm/nohash/32/mmu-44x.h

@@ -108,7 +108,7 @@ extern unsigned int tlb_44x_index;
 typedef struct {
 	unsigned int	id;
 	unsigned int	active;
-	unsigned long	vdso_base;
+	void __user	*vdso;
 } mm_context_t;
 
 /* patch sites */

arch/powerpc/include/asm/nohash/32/mmu-8xx.h

@@ -181,7 +181,7 @@ void mmu_pin_tlb(unsigned long top, bool readonly);
 typedef struct {
 	unsigned int id;
 	unsigned int active;
-	unsigned long vdso_base;
+	void __user *vdso;
 	void *pte_frag;
 } mm_context_t;
 

arch/powerpc/include/asm/nohash/mmu-book3e.h

@@ -238,7 +238,7 @@ extern unsigned int tlbcam_index;
 typedef struct {
 	unsigned int	id;
 	unsigned int	active;
-	unsigned long	vdso_base;
+	void __user	*vdso;
 } mm_context_t;
 
 /* Page size definitions, common between 32 and 64-bit

arch/powerpc/kernel/signal_32.c

@@ -801,8 +801,8 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
 	}
 
 	/* Save user registers on the stack */
-	if (vdso32_rt_sigtramp && tsk->mm->context.vdso_base) {
-		tramp = tsk->mm->context.vdso_base + vdso32_rt_sigtramp;
+	if (vdso32_rt_sigtramp && tsk->mm->context.vdso) {
+		tramp = (unsigned long)tsk->mm->context.vdso + vdso32_rt_sigtramp;
 	} else {
 		tramp = (unsigned long)mctx->mc_pad;
 		/* Set up the sigreturn trampoline: li r0,sigret; sc */
@@ -901,8 +901,8 @@ int handle_signal32(struct ksignal *ksig, sigset_t *oldset,
 	else
 		unsafe_save_user_regs(regs, mctx, tm_mctx, 1, failed);
 
-	if (vdso32_sigtramp && tsk->mm->context.vdso_base) {
-		tramp = tsk->mm->context.vdso_base + vdso32_sigtramp;
+	if (vdso32_sigtramp && tsk->mm->context.vdso) {
+		tramp = (unsigned long)tsk->mm->context.vdso + vdso32_sigtramp;
 	} else {
 		tramp = (unsigned long)mctx->mc_pad;
 		/* Set up the sigreturn trampoline: li r0,sigret; sc */

arch/powerpc/kernel/signal_64.c

@@ -854,8 +854,8 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 	tsk->thread.fp_state.fpscr = 0;
 
 	/* Set up to return from userspace. */
-	if (vdso64_rt_sigtramp && tsk->mm->context.vdso_base) {
-		regs->nip = tsk->mm->context.vdso_base + vdso64_rt_sigtramp;
+	if (vdso64_rt_sigtramp && tsk->mm->context.vdso) {
+		regs->nip = (unsigned long)tsk->mm->context.vdso + vdso64_rt_sigtramp;
 	} else {
 		err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
 		if (err)

arch/powerpc/kernel/vdso.c

@@ -123,7 +123,7 @@ static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struc
 	if (new_size != text_size + PAGE_SIZE)
 		return -EINVAL;
 
-	current->mm->context.vdso_base = new_vma->vm_start;
+	current->mm->context.vdso = (void __user *)new_vma->vm_start;
 
 	return 0;
 }
@@ -198,7 +198,7 @@ static int __arch_setup_additional_pages(struct linux_binprm *bprm, int uses_int
 	 * install_special_mapping or the perf counter mmap tracking code
 	 * will fail to recognise it as a vDSO.
 	 */
-	current->mm->context.vdso_base = vdso_base;
+	mm->context.vdso = (void __user *)vdso_base;
 
 	/*
 	 * our vma flags don't have VM_WRITE so by default, the process isn't
@@ -221,7 +221,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	struct mm_struct *mm = current->mm;
 	int rc;
 
-	mm->context.vdso_base = 0;
+	mm->context.vdso = NULL;
 
 	if (!vdso_ready)
 		return 0;
@@ -231,7 +231,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 
 	rc = __arch_setup_additional_pages(bprm, uses_interp);
 	if (rc)
-		mm->context.vdso_base = 0;
+		mm->context.vdso = NULL;
 
 	mmap_write_unlock(mm);
 	return rc;

arch/powerpc/perf/callchain_32.c

@@ -59,8 +59,8 @@ static int is_sigreturn_32_address(unsigned int nip, unsigned int fp)
 {
 	if (nip == fp + offsetof(struct signal_frame_32, mctx.mc_pad))
 		return 1;
-	if (vdso32_sigtramp && current->mm->context.vdso_base &&
-	    nip == current->mm->context.vdso_base + vdso32_sigtramp)
+	if (vdso32_sigtramp && current->mm->context.vdso &&
+	    nip == (unsigned long)current->mm->context.vdso + vdso32_sigtramp)
 		return 1;
 	return 0;
 }
@@ -70,8 +70,8 @@ static int is_rt_sigreturn_32_address(unsigned int nip, unsigned int fp)
 	if (nip == fp + offsetof(struct rt_signal_frame_32,
 				 uc.uc_mcontext.mc_pad))
 		return 1;
-	if (vdso32_rt_sigtramp && current->mm->context.vdso_base &&
-	    nip == current->mm->context.vdso_base + vdso32_rt_sigtramp)
+	if (vdso32_rt_sigtramp && current->mm->context.vdso &&
+	    nip == (unsigned long)current->mm->context.vdso + vdso32_rt_sigtramp)
 		return 1;
 	return 0;
 }

arch/powerpc/perf/callchain_64.c

@@ -68,8 +68,8 @@ static int is_sigreturn_64_address(unsigned long nip, unsigned long fp)
 {
 	if (nip == fp + offsetof(struct signal_frame_64, tramp))
 		return 1;
-	if (vdso64_rt_sigtramp && current->mm->context.vdso_base &&
-	    nip == current->mm->context.vdso_base + vdso64_rt_sigtramp)
+	if (vdso64_rt_sigtramp && current->mm->context.vdso &&
+	    nip == (unsigned long)current->mm->context.vdso + vdso64_rt_sigtramp)
 		return 1;
 	return 0;
 }