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Date: Fri, 2 Jan 2015 10:38:57 +0000
From: James Hogan <james.hogan@...tec.com>
To: Rickard Strandqvist <rickard_strandqvist@...ctrumdigital.se>,
Ralf Baechle <ralf@...ux-mips.org>,
Markos Chandras <markos.chandras@...tec.com>
CC: Paul Burton <paul.burton@...tec.com>,
Leonid Yegoshin <Leonid.Yegoshin@...tec.com>,
John Crispin <blogic@...nwrt.org>, <linux-mips@...ux-mips.org>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] arch: mips: kernel: traps: Remove some unused functions
On 01/01/15 17:48, Rickard Strandqvist wrote:
> Removes some functions that are not used anywhere:
> do_bp() do_ftlb() do_dsp() do_mcheck() do_mdmx() do_msa() do_msa_fpe()
>
> This was partially found by using a static code analysis program called cppcheck.
To elaborate on Leonid's comment, These functions are used from
arch/mips/kernel/genex.S. See BUILD_HANDLER assembly macro. Each one
builds a handle_* assembly function which saves appropriate exception
state and calls do_*() with return address pointing to
ret_from_exception. The handle_* functions are set as handlers for
various exceptions by set_except_vector() in arch/mips/kernel/traps.c.
Cheers
James
>
> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@...ctrumdigital.se>
> ---
> arch/mips/kernel/traps.c | 185 ----------------------------------------------
> 1 file changed, 185 deletions(-)
>
> diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
> index 22b19c2..59c8e0d 100644
> --- a/arch/mips/kernel/traps.c
> +++ b/arch/mips/kernel/traps.c
> @@ -854,85 +854,6 @@ static void do_trap_or_bp(struct pt_regs *regs, unsigned int code,
> }
> }
>
> -asmlinkage void do_bp(struct pt_regs *regs)
> -{
> - unsigned int opcode, bcode;
> - enum ctx_state prev_state;
> - unsigned long epc;
> - u16 instr[2];
> - mm_segment_t seg;
> -
> - seg = get_fs();
> - if (!user_mode(regs))
> - set_fs(KERNEL_DS);
> -
> - prev_state = exception_enter();
> - if (get_isa16_mode(regs->cp0_epc)) {
> - /* Calculate EPC. */
> - epc = exception_epc(regs);
> - if (cpu_has_mmips) {
> - if ((__get_user(instr[0], (u16 __user *)msk_isa16_mode(epc)) ||
> - (__get_user(instr[1], (u16 __user *)msk_isa16_mode(epc + 2)))))
> - goto out_sigsegv;
> - opcode = (instr[0] << 16) | instr[1];
> - } else {
> - /* MIPS16e mode */
> - if (__get_user(instr[0],
> - (u16 __user *)msk_isa16_mode(epc)))
> - goto out_sigsegv;
> - bcode = (instr[0] >> 6) & 0x3f;
> - do_trap_or_bp(regs, bcode, "Break");
> - goto out;
> - }
> - } else {
> - if (__get_user(opcode,
> - (unsigned int __user *) exception_epc(regs)))
> - goto out_sigsegv;
> - }
> -
> - /*
> - * There is the ancient bug in the MIPS assemblers that the break
> - * code starts left to bit 16 instead to bit 6 in the opcode.
> - * Gas is bug-compatible, but not always, grrr...
> - * We handle both cases with a simple heuristics. --macro
> - */
> - bcode = ((opcode >> 6) & ((1 << 20) - 1));
> - if (bcode >= (1 << 10))
> - bcode >>= 10;
> -
> - /*
> - * notify the kprobe handlers, if instruction is likely to
> - * pertain to them.
> - */
> - switch (bcode) {
> - case BRK_KPROBE_BP:
> - if (notify_die(DIE_BREAK, "debug", regs, bcode,
> - regs_to_trapnr(regs), SIGTRAP) == NOTIFY_STOP)
> - goto out;
> - else
> - break;
> - case BRK_KPROBE_SSTEPBP:
> - if (notify_die(DIE_SSTEPBP, "single_step", regs, bcode,
> - regs_to_trapnr(regs), SIGTRAP) == NOTIFY_STOP)
> - goto out;
> - else
> - break;
> - default:
> - break;
> - }
> -
> - do_trap_or_bp(regs, bcode, "Break");
> -
> -out:
> - set_fs(seg);
> - exception_exit(prev_state);
> - return;
> -
> -out_sigsegv:
> - force_sig(SIGSEGV, current);
> - goto out;
> -}
> -
> asmlinkage void do_tr(struct pt_regs *regs)
> {
> u32 opcode, tcode = 0;
> @@ -1297,46 +1218,6 @@ out:
> exception_exit(prev_state);
> }
>
> -asmlinkage void do_msa_fpe(struct pt_regs *regs)
> -{
> - enum ctx_state prev_state;
> -
> - prev_state = exception_enter();
> - die_if_kernel("do_msa_fpe invoked from kernel context!", regs);
> - force_sig(SIGFPE, current);
> - exception_exit(prev_state);
> -}
> -
> -asmlinkage void do_msa(struct pt_regs *regs)
> -{
> - enum ctx_state prev_state;
> - int err;
> -
> - prev_state = exception_enter();
> -
> - if (!cpu_has_msa || test_thread_flag(TIF_32BIT_FPREGS)) {
> - force_sig(SIGILL, current);
> - goto out;
> - }
> -
> - die_if_kernel("do_msa invoked from kernel context!", regs);
> -
> - err = enable_restore_fp_context(1);
> - if (err)
> - force_sig(SIGILL, current);
> -out:
> - exception_exit(prev_state);
> -}
> -
> -asmlinkage void do_mdmx(struct pt_regs *regs)
> -{
> - enum ctx_state prev_state;
> -
> - prev_state = exception_enter();
> - force_sig(SIGILL, current);
> - exception_exit(prev_state);
> -}
> -
> /*
> * Called with interrupts disabled.
> */
> @@ -1370,36 +1251,6 @@ asmlinkage void do_watch(struct pt_regs *regs)
> exception_exit(prev_state);
> }
>
> -asmlinkage void do_mcheck(struct pt_regs *regs)
> -{
> - const int field = 2 * sizeof(unsigned long);
> - int multi_match = regs->cp0_status & ST0_TS;
> - enum ctx_state prev_state;
> -
> - prev_state = exception_enter();
> - show_regs(regs);
> -
> - if (multi_match) {
> - printk("Index : %0x\n", read_c0_index());
> - printk("Pagemask: %0x\n", read_c0_pagemask());
> - printk("EntryHi : %0*lx\n", field, read_c0_entryhi());
> - printk("EntryLo0: %0*lx\n", field, read_c0_entrylo0());
> - printk("EntryLo1: %0*lx\n", field, read_c0_entrylo1());
> - printk("\n");
> - dump_tlb_all();
> - }
> -
> - show_code((unsigned int __user *) regs->cp0_epc);
> -
> - /*
> - * Some chips may have other causes of machine check (e.g. SB1
> - * graduation timer)
> - */
> - panic("Caught Machine Check exception - %scaused by multiple "
> - "matching entries in the TLB.",
> - (multi_match) ? "" : "not ");
> -}
> -
> asmlinkage void do_mt(struct pt_regs *regs)
> {
> int subcode;
> @@ -1436,14 +1287,6 @@ asmlinkage void do_mt(struct pt_regs *regs)
> }
>
>
> -asmlinkage void do_dsp(struct pt_regs *regs)
> -{
> - if (cpu_has_dsp)
> - panic("Unexpected DSP exception");
> -
> - force_sig(SIGILL, current);
> -}
> -
> asmlinkage void do_reserved(struct pt_regs *regs)
> {
> /*
> @@ -1609,34 +1452,6 @@ asmlinkage void cache_parity_error(void)
> panic("Can't handle the cache error!");
> }
>
> -asmlinkage void do_ftlb(void)
> -{
> - const int field = 2 * sizeof(unsigned long);
> - unsigned int reg_val;
> -
> - /* For the moment, report the problem and hang. */
> - if (cpu_has_mips_r2 &&
> - ((current_cpu_data.processor_id & 0xff0000) == PRID_COMP_MIPS)) {
> - pr_err("FTLB error exception, cp0_ecc=0x%08x:\n",
> - read_c0_ecc());
> - pr_err("cp0_errorepc == %0*lx\n", field, read_c0_errorepc());
> - reg_val = read_c0_cacheerr();
> - pr_err("c0_cacheerr == %08x\n", reg_val);
> -
> - if ((reg_val & 0xc0000000) == 0xc0000000) {
> - pr_err("Decoded c0_cacheerr: FTLB parity error\n");
> - } else {
> - pr_err("Decoded c0_cacheerr: %s cache fault in %s reference.\n",
> - reg_val & (1<<30) ? "secondary" : "primary",
> - reg_val & (1<<31) ? "data" : "insn");
> - }
> - } else {
> - pr_err("FTLB error exception\n");
> - }
> - /* Just print the cacheerr bits for now */
> - cache_parity_error();
> -}
> -
> /*
> * SDBBP EJTAG debug exception handler.
> * We skip the instruction and return to the next instruction.
>
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