ath10k: use kzalloc to read for ath10k_sdio_hif_diag_read

When use command to read values, it crashed.

command:
dd if=/sys/kernel/debug/ieee80211/phy0/ath10k/mem_value count=1 bs=4 skip=$((0x100233))

It will call to ath10k_sdio_hif_diag_read with address = 0x4008cc and buf_len = 4.

Then system crash:
[ 1786.013258] Unable to handle kernel paging request at virtual address ffffffc00bd45000
[ 1786.013273] Mem abort info:
[ 1786.013281]   ESR = 0x96000045
[ 1786.013291]   Exception class = DABT (current EL), IL = 32 bits
[ 1786.013299]   SET = 0, FnV = 0
[ 1786.013307]   EA = 0, S1PTW = 0
[ 1786.013314] Data abort info:
[ 1786.013322]   ISV = 0, ISS = 0x00000045
[ 1786.013330]   CM = 0, WnR = 1
[ 1786.013342] swapper pgtable: 4k pages, 39-bit VAs, pgdp = 000000008542a60e
[ 1786.013350] [ffffffc00bd45000] pgd=0000000000000000, pud=0000000000000000
[ 1786.013368] Internal error: Oops: 96000045 [#1] PREEMPT SMP
[ 1786.013609] Process swapper/0 (pid: 0, stack limit = 0x0000000084b153c6)
[ 1786.013623] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.19.86 raspberrypi#137
[ 1786.013631] Hardware name: MediaTek krane sku176 board (DT)
[ 1786.013643] pstate: 80000085 (Nzcv daIf -PAN -UAO)
[ 1786.013662] pc : __memcpy+0x94/0x180
[ 1786.013678] lr : swiotlb_tbl_unmap_single+0x84/0x150
[ 1786.013686] sp : ffffff8008003c60
[ 1786.013694] x29: ffffff8008003c90 x28: ffffffae96411f80
[ 1786.013708] x27: ffffffae960d2018 x26: ffffff8019a4b9a8
[ 1786.013721] x25: 0000000000000000 x24: 0000000000000001
[ 1786.013734] x23: ffffffae96567000 x22: 00000000000051d4
[ 1786.013747] x21: 0000000000000000 x20: 00000000fe6e9000
[ 1786.013760] x19: 0000000000000004 x18: 0000000000000020
[ 1786.013773] x17: 0000000000000001 x16: 0000000000000000
[ 1786.013787] x15: 00000000ffffffff x14: 00000000000044c0
[ 1786.013800] x13: 0000000000365ba4 x12: 0000000000000000
[ 1786.013813] x11: 0000000000000001 x10: 00000037be6e9000
[ 1786.013826] x9 : ffffffc940000000 x8 : 000000000bd45000
[ 1786.013839] x7 : 0000000000000000 x6 : ffffffc00bd45000
[ 1786.013852] x5 : 0000000000000000 x4 : 0000000000000000
[ 1786.013865] x3 : 0000000000000c00 x2 : 0000000000000004
[ 1786.013878] x1 : fffffff7be6e9004 x0 : ffffffc00bd45000
[ 1786.013891] Call trace:
[ 1786.013903]  __memcpy+0x94/0x180
[ 1786.013914]  unmap_single+0x6c/0x84
[ 1786.013925]  swiotlb_unmap_sg_attrs+0x54/0x80
[ 1786.013938]  __swiotlb_unmap_sg_attrs+0x8c/0xa4
[ 1786.013952]  msdc_unprepare_data+0x6c/0x84
[ 1786.013963]  msdc_request_done+0x58/0x84
[ 1786.013974]  msdc_data_xfer_done+0x1a0/0x1c8
[ 1786.013985]  msdc_irq+0x12c/0x17c
[ 1786.013996]  __handle_irq_event_percpu+0xe4/0x250
[ 1786.014006]  handle_irq_event_percpu+0x28/0x68
[ 1786.014015]  handle_irq_event+0x48/0x78
[ 1786.014026]  handle_fasteoi_irq+0xd0/0x1a0
[ 1786.014039]  __handle_domain_irq+0x84/0xc4
[ 1786.014050]  gic_handle_irq+0x124/0x1a4
[ 1786.014059]  el1_irq+0xb0/0x128
[ 1786.014072]  cpuidle_enter_state+0x298/0x328
[ 1786.014082]  cpuidle_enter+0x30/0x40
[ 1786.014094]  do_idle+0x190/0x268
[ 1786.014104]  cpu_startup_entry+0x24/0x28
[ 1786.014116]  rest_init+0xd4/0xe0
[ 1786.014126]  start_kernel+0x30c/0x38c
[ 1786.014139] Code: f8408423 f80084c3 36100062 b8404423 (b80044c3)
[ 1786.014150] ---[ end trace 3b02ddb698ea69ee ]---
[ 1786.015415] Kernel panic - not syncing: Fatal exception in interrupt
[ 1786.015433] SMP: stopping secondary CPUs
[ 1786.015447] Kernel Offset: 0x2e8d200000 from 0xffffff8008000000
[ 1786.015458] CPU features: 0x0,2188200c
[ 1786.015466] Memory Limit: none

For sdio chip, it need the memory which is kmalloc, if it is
vmalloc from ath10k_mem_value_read, then it have a memory error.
kzalloc of ath10k_sdio_hif_diag_read32 is the correct type, so
add kzalloc in ath10k_sdio_hif_diag_read to replace the buffer
which is vmalloc from ath10k_mem_value_read.

This patch only effect sdio chip.

Tested with QCA6174 SDIO with firmware WLAN.RMH.4.4.1-00029.

Signed-off-by: Wen Gong <[email protected]>
Signed-off-by: Kalle Valo <[email protected]>

drivers/net/wireless/ath/ath10k/sdio.c

@@ -1650,23 +1650,33 @@ static int ath10k_sdio_hif_diag_read(struct ath10k *ar, u32 address, void *buf,
 				     size_t buf_len)
 {
 	int ret;
+	void *mem;
+
+	mem = kzalloc(buf_len, GFP_KERNEL);
+	if (!mem)
+		return -ENOMEM;
 
 	/* set window register to start read cycle */
 	ret = ath10k_sdio_write32(ar, MBOX_WINDOW_READ_ADDR_ADDRESS, address);
 	if (ret) {
 		ath10k_warn(ar, "failed to set mbox window read address: %d", ret);
-		return ret;
+		goto out;
 	}
 
 	/* read the data */
-	ret = ath10k_sdio_read(ar, MBOX_WINDOW_DATA_ADDRESS, buf, buf_len);
+	ret = ath10k_sdio_read(ar, MBOX_WINDOW_DATA_ADDRESS, mem, buf_len);
 	if (ret) {
 		ath10k_warn(ar, "failed to read from mbox window data address: %d\n",
 			    ret);
-		return ret;
+		goto out;
 	}
 
-	return 0;
+	memcpy(buf, mem, buf_len);
+
+out:
+	kfree(mem);
+
+	return ret;
 }
 
 static int ath10k_sdio_hif_diag_read32(struct ath10k *ar, u32 address,