treewide: Remove uninitialized_var() usage

Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/[email protected]/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky <[email protected]> # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe <[email protected]> # IB
Acked-by: Kalle Valo <[email protected]> # wireless drivers
Reviewed-by: Chao Yu <[email protected]> # erofs
Signed-off-by: Kees Cook <[email protected]>

Author: kees

arch/arm/mach-sa1100/assabet.c

@@ -652,7 +652,7 @@ static void __init map_sa1100_gpio_regs( void )
  */
 static void __init get_assabet_scr(void)
 {
-	unsigned long uninitialized_var(scr), i;
+	unsigned long scr, i;
 
 	GPDR |= 0x3fc;			/* Configure GPIO 9:2 as outputs */
 	GPSR = 0x3fc;			/* Write 0xFF to GPIO 9:2 */

arch/arm/mm/alignment.c

@@ -799,7 +799,7 @@ static int alignment_get_thumb(struct pt_regs *regs, u16 *ip, u16 *inst)
 static int
 do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 {
-	union offset_union uninitialized_var(offset);
+	union offset_union offset;
 	unsigned long instrptr;
 	int (*handler)(unsigned long addr, u32 instr, struct pt_regs *regs);
 	unsigned int type;

arch/ia64/kernel/process.c

@@ -445,7 +445,7 @@ static void
 do_copy_task_regs (struct task_struct *task, struct unw_frame_info *info, void *arg)
 {
 	unsigned long mask, sp, nat_bits = 0, ar_rnat, urbs_end, cfm;
-	unsigned long uninitialized_var(ip);	/* GCC be quiet */
+	unsigned long ip;
 	elf_greg_t *dst = arg;
 	struct pt_regs *pt;
 	char nat;

arch/ia64/mm/discontig.c

@@ -180,7 +180,7 @@ static void *per_cpu_node_setup(void *cpu_data, int node)
 void __init setup_per_cpu_areas(void)
 {
 	struct pcpu_alloc_info *ai;
-	struct pcpu_group_info *uninitialized_var(gi);
+	struct pcpu_group_info *gi;
 	unsigned int *cpu_map;
 	void *base;
 	unsigned long base_offset;

arch/ia64/mm/tlb.c

@@ -369,7 +369,7 @@ EXPORT_SYMBOL(flush_tlb_range);
 
 void ia64_tlb_init(void)
 {
-	ia64_ptce_info_t uninitialized_var(ptce_info); /* GCC be quiet */
+	ia64_ptce_info_t ptce_info;
 	u64 tr_pgbits;
 	long status;
 	pal_vm_info_1_u_t vm_info_1;

arch/mips/lib/dump_tlb.c

@@ -79,7 +79,7 @@ static void dump_tlb(int first, int last)
 	unsigned int pagemask, guestctl1 = 0, c0, c1, i;
 	unsigned long asidmask = cpu_asid_mask(&current_cpu_data);
 	int asidwidth = DIV_ROUND_UP(ilog2(asidmask) + 1, 4);
-	unsigned long uninitialized_var(s_mmid);
+	unsigned long s_mmid;
 #ifdef CONFIG_32BIT
 	bool xpa = cpu_has_xpa && (read_c0_pagegrain() & PG_ELPA);
 	int pwidth = xpa ? 11 : 8;

arch/mips/mm/init.c

@@ -83,7 +83,7 @@ void setup_zero_pages(void)
 static void *__kmap_pgprot(struct page *page, unsigned long addr, pgprot_t prot)
 {
 	enum fixed_addresses idx;
-	unsigned int uninitialized_var(old_mmid);
+	unsigned int old_mmid;
 	unsigned long vaddr, flags, entrylo;
 	unsigned long old_ctx;
 	pte_t pte;

arch/mips/mm/tlb-r4k.c

@@ -119,7 +119,7 @@ void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 		if (size <= (current_cpu_data.tlbsizeftlbsets ?
 			     current_cpu_data.tlbsize / 8 :
 			     current_cpu_data.tlbsize / 2)) {
-			unsigned long old_entryhi, uninitialized_var(old_mmid);
+			unsigned long old_entryhi, old_mmid;
 			int newpid = cpu_asid(cpu, mm);
 
 			old_entryhi = read_c0_entryhi();
@@ -213,7 +213,7 @@ void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 	int cpu = smp_processor_id();
 
 	if (cpu_context(cpu, vma->vm_mm) != 0) {
-		unsigned long uninitialized_var(old_mmid);
+		unsigned long old_mmid;
 		unsigned long flags, old_entryhi;
 		int idx;
 
@@ -382,7 +382,7 @@ void add_wired_entry(unsigned long entrylo0, unsigned long entrylo1,
 #ifdef CONFIG_XPA
 	panic("Broken for XPA kernels");
 #else
-	unsigned int uninitialized_var(old_mmid);
+	unsigned int old_mmid;
 	unsigned long flags;
 	unsigned long wired;
 	unsigned long old_pagemask;

arch/powerpc/kvm/book3s_64_mmu_radix.c

@@ -33,7 +33,7 @@ unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid,
 					      gva_t eaddr, void *to, void *from,
 					      unsigned long n)
 {
-	int uninitialized_var(old_pid), old_lpid;
+	int old_pid, old_lpid;
 	unsigned long quadrant, ret = n;
 	bool is_load = !!to;
 

arch/powerpc/kvm/powerpc.c

@@ -1110,7 +1110,7 @@ static inline u32 dp_to_sp(u64 fprd)
 static void kvmppc_complete_mmio_load(struct kvm_vcpu *vcpu)
 {
 	struct kvm_run *run = vcpu->run;
-	u64 uninitialized_var(gpr);
+	u64 gpr;
 
 	if (run->mmio.len > sizeof(gpr)) {
 		printk(KERN_ERR "bad MMIO length: %d\n", run->mmio.len);