[PATCH v4] lib: fix pointer of type 'void *' used in arithmetic
Jessica Clarke
jrtc27 at jrtc27.com
Thu Jan 13 08:09:42 PST 2022
On 13 Jan 2022, at 16:07, Jessica Clarke <jrtc27 at jrtc27.com> wrote:
>
> On 13 Jan 2022, at 16:00, Xiang W <wxjstz at 126.com> wrote:
>>
>> 在 2022-01-13星期四的 14:55 +0200，Jukka Laitinen写道：
>>> Using "void *" in arithmetic causes errors with strict compiler
>>> settings:
>>> "error: pointer of type 'void *' used in arithmetic [-Werror=pointer-
>>> arith]"
>>>
>>> Avoid these by calculating on "char *" where 1-byte data size is
>>> assumed.
>>>
>> char has a specific meaning, such modification is not conducive to code
>> reading.
>
> This is extremely idiomatic, you see it everywhere in systems code.
See [1] for a crude estimate of how much code uses this idiom.
Jess
[1] https://codesearch.debian.net/search?q=%5C*%5C%29%5C%28%5C%28char+%5C*%5C%29%5BA-Za-z0-9_-%5D%2B+%5C%2B&literal=0&perpkg=1
>> I suggest adding an inline function
>>
>> inline void * ptr_with_offset(void *p, unsigned long off)
>> {
>> return (void *)((uintptr_t)p + off);
>> }
>
> This only serves to complicate, and using uintptr_t when you don’t need
> to is bad practice. Plus your version won’t work with volatile and/or
> const qualified pointers without warning if the relevant warnings are
> enabled.
>
> Jess
>
>> Regards,
>> Xiang W
>>> Signed-off-by: Jukka Laitinen <jukkax at ssrc.tii.ae>
>>> ---
>>> include/sbi/sbi_scratch.h | 4 ++--
>>> lib/sbi/sbi_fifo.c | 6 +++---
>>> lib/sbi/sbi_string.c | 4 ++--
>>> lib/utils/i2c/fdt_i2c_sifive.c | 4 ++--
>>> lib/utils/irqchip/fdt_irqchip_plic.c | 2 +-
>>> lib/utils/irqchip/plic.c | 8 ++++----
>>> lib/utils/reset/fdt_reset_sunxi_wdt.c | 4 ++--
>>> lib/utils/reset/fdt_reset_thead.c | 4 ++--
>>> lib/utils/serial/gaisler-uart.c | 4 ++--
>>> lib/utils/serial/shakti-uart.c | 4 ++--
>>> lib/utils/serial/sifive-uart.c | 4 ++--
>>> lib/utils/serial/uart8250.c | 4 ++--
>>> lib/utils/timer/aclint_mtimer.c | 2 +-
>>> 13 files changed, 27 insertions(+), 27 deletions(-)
>>>
>>> diff --git a/include/sbi/sbi_scratch.h b/include/sbi/sbi_scratch.h
>>> index 186a40c..0c27307 100644
>>> --- a/include/sbi/sbi_scratch.h
>>> +++ b/include/sbi/sbi_scratch.h
>>> @@ -104,11 +104,11 @@ unsigned long sbi_scratch_alloc_offset(unsigned
>>> long size);
>>> void sbi_scratch_free_offset(unsigned long offset);
>>>
>>> /** Get pointer from offset in sbi_scratch */
>>> -#define sbi_scratch_offset_ptr(scratch, offset) ((void
>>> *)scratch + (offset))
>>> +#define sbi_scratch_offset_ptr(scratch, offset) (void *)((char
>>> *)(scratch) + (offset))
>>>
>>> /** Get pointer from offset in sbi_scratch for current HART */
>>> #define sbi_scratch_thishart_offset_ptr(offset) \
>>> - ((void *)sbi_scratch_thishart_ptr() + (offset))
>>> + (void *)((char *)sbi_scratch_thishart_ptr() + (offset))
>>>
>>> /** HART id to scratch table */
>>> extern struct sbi_scratch *hartid_to_scratch_table[];
>>> diff --git a/lib/sbi/sbi_fifo.c b/lib/sbi/sbi_fifo.c
>>> index 589cc18..68d6039 100644
>>> --- a/lib/sbi/sbi_fifo.c
>>> +++ b/lib/sbi/sbi_fifo.c
>>> @@ -66,7 +66,7 @@ static inline void __sbi_fifo_enqueue(struct
>>> sbi_fifo *fifo, void *data)
>>> if (head >= fifo->num_entries)
>>> head = head - fifo->num_entries;
>>>
>>> - sbi_memcpy(fifo->queue + head * fifo->entry_size, data, fifo-
>>>> entry_size);
>>> + sbi_memcpy((char *)fifo->queue + head * fifo->entry_size,
>>> data, fifo->entry_size);
>>>
>>> fifo->avail++;
>>> }
>>> @@ -142,7 +142,7 @@ int sbi_fifo_inplace_update(struct sbi_fifo *fifo,
>>> void *in,
>>> index = fifo->tail + i;
>>> if (index >= fifo->num_entries)
>>> index -= fifo->num_entries;
>>> - entry = (void *)fifo->queue + (u32)index * fifo-
>>>> entry_size;
>>> + entry = (char *)fifo->queue + (u32)index * fifo-
>>>> entry_size;
>>> ret = fptr(in, entry);
>>>
>>> if (ret == SBI_FIFO_SKIP || ret == SBI_FIFO_UPDATED) {
>>> @@ -184,7 +184,7 @@ int sbi_fifo_dequeue(struct sbi_fifo *fifo, void
>>> *data)
>>> return SBI_ENOENT;
>>> }
>>>
>>> - sbi_memcpy(data, fifo->queue + (u32)fifo->tail * fifo-
>>>> entry_size,
>>> + sbi_memcpy(data, (char *)fifo->queue + (u32)fifo->tail * fifo-
>>>> entry_size,
>>> fifo->entry_size);
>>>
>>> fifo->avail--;
>>> diff --git a/lib/sbi/sbi_string.c b/lib/sbi/sbi_string.c
>>> index c87bce9..c163f31 100644
>>> --- a/lib/sbi/sbi_string.c
>>> +++ b/lib/sbi/sbi_string.c
>>> @@ -149,8 +149,8 @@ void *sbi_memmove(void *dest, const void *src,
>>> size_t count)
>>> count--;
>>> }
>>> } else {
>>> - temp1 = dest + count - 1;
>>> - temp2 = src + count - 1;
>>> + temp1 = (char *)dest + count - 1;
>>> + temp2 = (char *)src + count - 1;
>>>
>>> while (count > 0) {
>>> *temp1-- = *temp2--;
>>> diff --git a/lib/utils/i2c/fdt_i2c_sifive.c
>>> b/lib/utils/i2c/fdt_i2c_sifive.c
>>> index 871241a..195541c 100644
>>> --- a/lib/utils/i2c/fdt_i2c_sifive.c
>>> +++ b/lib/utils/i2c/fdt_i2c_sifive.c
>>> @@ -56,13 +56,13 @@ extern struct fdt_i2c_adapter
>>> fdt_i2c_adapter_sifive;
>>> static inline void sifive_i2c_setreg(struct sifive_i2c_adapter *adap,
>>> uint8_t reg, uint8_t value)
>>> {
>>> - writel(value, (volatile void *)adap->addr + reg);
>>> + writel(value, (volatile char *)adap->addr + reg);
>>> }
>>>
>>> static inline uint8_t sifive_i2c_getreg(struct sifive_i2c_adapter
>>> *adap,
>>> uint8_t reg)
>>> {
>>> - return readl((volatile void *)adap->addr + reg);
>>> + return readl((volatile char *)adap->addr + reg);
>>> }
>>>
>>> static int sifive_i2c_adapter_rxack(struct sifive_i2c_adapter *adap)
>>> diff --git a/lib/utils/irqchip/fdt_irqchip_plic.c
>>> b/lib/utils/irqchip/fdt_irqchip_plic.c
>>> index 8d375be..b2d2a1b 100644
>>> --- a/lib/utils/irqchip/fdt_irqchip_plic.c
>>> +++ b/lib/utils/irqchip/fdt_irqchip_plic.c
>>> @@ -116,7 +116,7 @@ static int irqchip_plic_cold_init(void *fdt, int
>>> nodeoff,
>>>
>>> static void thead_plic_plat_init(struct plic_data *pd)
>>> {
>>> - writel_relaxed(BIT(0), (void *)pd->addr +
>>> THEAD_PLIC_CTRL_REG);
>>> + writel_relaxed(BIT(0), (char *)pd->addr +
>>> THEAD_PLIC_CTRL_REG);
>>> }
>>>
>>> static const struct fdt_match irqchip_plic_match[] = {
>>> diff --git a/lib/utils/irqchip/plic.c b/lib/utils/irqchip/plic.c
>>> index 7665c62..0f58f3e 100644
>>> --- a/lib/utils/irqchip/plic.c
>>> +++ b/lib/utils/irqchip/plic.c
>>> @@ -23,7 +23,7 @@
>>>
>>> static void plic_set_priority(struct plic_data *plic, u32 source, u32
>>> val)
>>> {
>>> - volatile void *plic_priority = (void *)plic->addr +
>>> + volatile void *plic_priority = (char *)plic->addr +
>>> PLIC_PRIORITY_BASE + 4 * source;
>>> writel(val, plic_priority);
>>> }
>>> @@ -35,19 +35,19 @@ void plic_set_thresh(struct plic_data *plic, u32
>>> cntxid, u32 val)
>>> if (!plic)
>>> return;
>>>
>>> - plic_thresh = (void *)plic->addr +
>>> + plic_thresh = (char *)plic->addr +
>>> PLIC_CONTEXT_BASE + PLIC_CONTEXT_STRIDE *
>>> cntxid;
>>> writel(val, plic_thresh);
>>> }
>>>
>>> void plic_set_ie(struct plic_data *plic, u32 cntxid, u32 word_index,
>>> u32 val)
>>> {
>>> - volatile void *plic_ie;
>>> + volatile char *plic_ie;
>>>
>>> if (!plic)
>>> return;
>>>
>>> - plic_ie = (void *)plic->addr +
>>> + plic_ie = (char *)plic->addr +
>>> PLIC_ENABLE_BASE + PLIC_ENABLE_STRIDE * cntxid;
>>> writel(val, plic_ie + word_index * 4);
>>> }
>>> diff --git a/lib/utils/reset/fdt_reset_sunxi_wdt.c
>>> b/lib/utils/reset/fdt_reset_sunxi_wdt.c
>>> index 6d1b5b7..446d32b 100644
>>> --- a/lib/utils/reset/fdt_reset_sunxi_wdt.c
>>> +++ b/lib/utils/reset/fdt_reset_sunxi_wdt.c
>>> @@ -19,7 +19,7 @@
>>>
>>> #define WDT_MODE_REG 0x18
>>>
>>> -static volatile void *sunxi_wdt_base;
>>> +static volatile char *sunxi_wdt_base;
>>>
>>> static int sunxi_wdt_system_reset_check(u32 type, u32 reason)
>>> {
>>> @@ -59,7 +59,7 @@ static int sunxi_wdt_reset_init(void *fdt, int
>>> nodeoff,
>>> if (rc < 0 || !reg_addr)
>>> return SBI_ENODEV;
>>>
>>> - sunxi_wdt_base = (volatile void *)(unsigned long)reg_addr;
>>> + sunxi_wdt_base = (volatile char *)(unsigned long)reg_addr;
>>>
>>> sbi_system_reset_add_device(&sunxi_wdt_reset);
>>>
>>> diff --git a/lib/utils/reset/fdt_reset_thead.c
>>> b/lib/utils/reset/fdt_reset_thead.c
>>> index d491687..def4997 100644
>>> --- a/lib/utils/reset/fdt_reset_thead.c
>>> +++ b/lib/utils/reset/fdt_reset_thead.c
>>> @@ -59,7 +59,7 @@ extern void __thead_pre_start_warm(void);
>>> static int thead_reset_init(void *fdt, int nodeoff,
>>> const struct fdt_match *match)
>>> {
>>> - void *p;
>>> + char *p;
>>> const fdt64_t *val;
>>> const fdt32_t *val_w;
>>> int len, i;
>>> @@ -91,7 +91,7 @@ static int thead_reset_init(void *fdt, int nodeoff,
>>> /* Custom reset method for secondary harts */
>>> val = fdt_getprop(fdt, nodeoff, "entry-reg", &len);
>>> if (len > 0 && val) {
>>> - p = (void *)(ulong)fdt64_to_cpu(*val);
>>> + p = (char *)fdt64_to_cpu(*val);
>>>
>>> val_w = fdt_getprop(fdt, nodeoff, "entry-cnt", &len);
>>> if (len > 0 && val_w) {
>>> diff --git a/lib/utils/serial/gaisler-uart.c
>>> b/lib/utils/serial/gaisler-uart.c
>>> index 49298e9..5f30ee4 100644
>>> --- a/lib/utils/serial/gaisler-uart.c
>>> +++ b/lib/utils/serial/gaisler-uart.c
>>> @@ -29,7 +29,7 @@
>>>
>>> /* clang-format on */
>>>
>>> -static volatile void *uart_base;
>>> +static volatile char *uart_base;
>>>
>>> static u32 get_reg(u32 num)
>>> {
>>> @@ -67,7 +67,7 @@ int gaisler_uart_init(unsigned long base, u32
>>> in_freq, u32 baudrate)
>>> {
>>> u32 ctrl;
>>>
>>> - uart_base = (volatile void *)base;
>>> + uart_base = (volatile char *)base;
>>>
>>> /* Configure baudrate */
>>> if (in_freq)
>>> diff --git a/lib/utils/serial/shakti-uart.c b/lib/utils/serial/shakti-
>>> uart.c
>>> index e77a985..5f2fe75 100644
>>> --- a/lib/utils/serial/shakti-uart.c
>>> +++ b/lib/utils/serial/shakti-uart.c
>>> @@ -21,7 +21,7 @@
>>> #define UART_TX_FULL 0x2
>>> #define UART_RX_FULL 0x8
>>>
>>> -static volatile void *uart_base;
>>> +static volatile char *uart_base;
>>>
>>> static void shakti_uart_putc(char ch)
>>> {
>>> @@ -46,7 +46,7 @@ static struct sbi_console_device shakti_console = {
>>>
>>> int shakti_uart_init(unsigned long base, u32 in_freq, u32 baudrate)
>>> {
>>> - uart_base = (volatile void *)base;
>>> + uart_base = (volatile char *)base;
>>> u16 baud = (u16)(in_freq/(16 * baudrate));
>>> writew(baud, uart_base + REG_BAUD);
>>>
>>> diff --git a/lib/utils/serial/sifive-uart.c b/lib/utils/serial/sifive-
>>> uart.c
>>> index 57d80fa..9478a77 100644
>>> --- a/lib/utils/serial/sifive-uart.c
>>> +++ b/lib/utils/serial/sifive-uart.c
>>> @@ -29,7 +29,7 @@
>>>
>>> /* clang-format on */
>>>
>>> -static volatile void *uart_base;
>>> +static volatile char *uart_base;
>>> static u32 uart_in_freq;
>>> static u32 uart_baudrate;
>>>
>>> @@ -90,7 +90,7 @@ static struct sbi_console_device sifive_console = {
>>>
>>> int sifive_uart_init(unsigned long base, u32 in_freq, u32 baudrate)
>>> {
>>> - uart_base = (volatile void *)base;
>>> + uart_base = (volatile char *)base;
>>> uart_in_freq = in_freq;
>>> uart_baudrate = baudrate;
>>>
>>> diff --git a/lib/utils/serial/uart8250.c b/lib/utils/serial/uart8250.c
>>> index 1cf6624..142f8dc 100644
>>> --- a/lib/utils/serial/uart8250.c
>>> +++ b/lib/utils/serial/uart8250.c
>>> @@ -39,7 +39,7 @@
>>>
>>> /* clang-format on */
>>>
>>> -static volatile void *uart8250_base;
>>> +static volatile char *uart8250_base;
>>> static u32 uart8250_in_freq;
>>> static u32 uart8250_baudrate;
>>> static u32 uart8250_reg_width;
>>> @@ -95,7 +95,7 @@ int uart8250_init(unsigned long base, u32 in_freq,
>>> u32 baudrate, u32 reg_shift,
>>> {
>>> u16 bdiv;
>>>
>>> - uart8250_base = (volatile void *)base;
>>> + uart8250_base = (volatile char *)base;
>>> uart8250_reg_shift = reg_shift;
>>> uart8250_reg_width = reg_width;
>>> uart8250_in_freq = in_freq;
>>> diff --git a/lib/utils/timer/aclint_mtimer.c
>>> b/lib/utils/timer/aclint_mtimer.c
>>> index 62e87f7..2532b63 100644
>>> --- a/lib/utils/timer/aclint_mtimer.c
>>> +++ b/lib/utils/timer/aclint_mtimer.c
>>> @@ -47,7 +47,7 @@ static u64 mtimer_time_rd32(volatile u64 *addr)
>>> static void mtimer_time_wr32(bool timecmp, u64 value, volatile u64
>>> *addr)
>>> {
>>> writel_relaxed((timecmp) ? -1U : 0U, (void *)(addr));
>>> - writel_relaxed((u32)(value >> 32), (void *)(addr) + 0x04);
>>> + writel_relaxed((u32)(value >> 32), (char *)(addr) + 0x04);
>>> writel_relaxed((u32)value, (void *)(addr));
>>> }
>>>
>>> --
>>> 2.25.1
>>>
>>>
>>
>>
>>
>> --
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>
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