kernel.git/arch/powerpc/include/asm/inst.h, branch linux-5.13.y

powerpc/inst: Fix sparse detection on get_user_instr()

2021-07-20T14:00:18Z

[ Upstream commit b3a9e523237013477bea914b7fbfbe420428b988 ] get_user_instr() lacks sparse detection for the __user tag. This is because __gui_ptr is assigned with a cast. Fix that by adding a __chk_user_ptr() Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/0320e5b41a794fd456ab8c5993bbfadcf9e1d8b4.1621516826.git.christophe.leroy@csgroup.eu Signed-off-by: Sasha Levin

powerpc: Rename probe_kernel_read_inst()

2021-04-21T12:52:33Z

When probe_kernel_read_inst() was created, it was to mimic probe_kernel_read() function. Since then, probe_kernel_read() has been renamed copy_from_kernel_nofault(). Rename probe_kernel_read_inst() into copy_inst_from_kernel_nofault(). Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/b783d1f7cdb8914992384a669a2af57051b6bdcf.1618405715.git.christophe.leroy@csgroup.eu

powerpc: Make probe_kernel_read_inst() common to PPC32 and PPC64

2021-04-21T12:52:33Z

We have two independant versions of probe_kernel_read_inst(), one for PPC32 and one for PPC64. The PPC32 is identical to the first part of the PPC64 version. The remaining part of PPC64 version is not relevant for PPC32, but not contradictory, so we can easily have a common function with the PPC64 part opted out via a IS_ENABLED(CONFIG_PPC64). The only need is to add a version of ppc_inst_prefix() for PPC32. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/f7b9dfddef3b3760182c7e5466356c121a293dc9.1618405715.git.christophe.leroy@csgroup.eu

powerpc: Remove probe_user_read_inst()

2021-04-21T12:52:33Z

Its name comes from former probe_user_read() function. That function is now called copy_from_user_nofault(). probe_user_read_inst() uses copy_from_user_nofault() to read only a few bytes. It is suboptimal. It does the same as get_user_inst() but in addition disables page faults. But on the other hand, it is not used for the time being. So remove it for now. If one day it is really needed, we can give it a new name more in line with today's naming, and implement it using get_user_inst() Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/5f6f82572242a59bfee1e19a71194d8f7ef5fca4.1618405715.git.christophe.leroy@csgroup.eu

powerpc/inst: ppc_inst_as_u64() becomes ppc_inst_as_ulong()

2021-04-21T12:52:32Z

In order to simplify use on PPC32, change ppc_inst_as_u64() into ppc_inst_as_ulong() that returns the 32 bits instruction on PPC32. Will be used when porting OPTPROBES to PPC32. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/22cadf29620664b600b82026d2a72b8b23351777.1618927318.git.christophe.leroy@csgroup.eu

powerpc/uaccess: Move get_user_instr helpers in asm/inst.h

2021-04-03T10:21:45Z

Those helpers use get_user helpers but they don't participate in their implementation, so they do not belong to asm/uaccess.h Move them in asm/inst.h Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/2c6e83581b4fa434aa7cf2fa7714c41e98f57007.1615398265.git.christophe.leroy@csgroup.eu

powerpc: Add a ppc_inst_as_str() helper

2020-07-23T07:41:36Z

There are quite a few places where instructions are printed, this is done using a '%x' format specifier. With the introduction of prefixed instructions, this does not work well. Currently in these places, ppc_inst_val() is used for the value for %x so only the first word of prefixed instructions are printed. When the instructions are word instructions, only a single word should be printed. For prefixed instructions both the prefix and suffix should be printed. To accommodate both of these situations, instead of a '%x' specifier use '%s' and introduce a helper, __ppc_inst_as_str() which returns a char *. The char * __ppc_inst_as_str() returns is buffer that is passed to it by the caller. It is cumbersome to require every caller of __ppc_inst_as_str() to now declare a buffer. To make it more convenient to use __ppc_inst_as_str(), wrap it in a macro that uses a compound statement to allocate a buffer on the caller's stack before calling it. Signed-off-by: Jordan Niethe Reviewed-by: Joel Stanley Acked-by: Segher Boessenkool [mpe: Drop 0x prefix to match most existings uses, especially xmon] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200602052728.18227-1-jniethe5@gmail.com

powerpc: Add ppc_inst_as_u64()

2020-05-26T13:36:57Z

The code patching code wants to get the value of a struct ppc_inst as a u64 when the instruction is prefixed, so we can pass the u64 down to __put_user_asm() and write it with a single store. The optprobes code wants to load a struct ppc_inst as an immediate into a register so it is useful to have it as a u64 to use the existing helper function. Currently this is a bit awkward because the value differs based on the CPU endianness, so add a helper to do the conversion. This fixes the usage in arch_prepare_optimized_kprobe() which was previously incorrect on big endian. Fixes: 650b55b707fd ("powerpc: Add prefixed instructions to instruction data type") Signed-off-by: Michael Ellerman Tested-by: Jordan Niethe Link: https://lore.kernel.org/r/20200526072630.2487363-1-mpe@ellerman.id.au

powerpc: Add ppc_inst_next()

2020-05-26T13:36:51Z

In a few places we want to calculate the address of the next instruction. Previously that was simple, we just added 4 bytes, or if using a u32 * we incremented that pointer by 1. But prefixed instructions make it more complicated, we need to advance by either 4 or 8 bytes depending on the actual instruction. We also can't do pointer arithmetic using struct ppc_inst, because it is always 8 bytes in size on 64-bit, even though we might only need to advance by 4 bytes. So add a ppc_inst_next() helper which calculates the location of the next instruction, if the given instruction was located at the given address. Note the instruction doesn't need to actually be at the address in memory. Although it would seem natural for the value to be passed by value, that makes it too easy to write a loop that will read off the end of a page, eg: for (; src < end; src = ppc_inst_next(src, *src), dest = ppc_inst_next(dest, *dest)) As noticed by Christophe and Jordan, if end is the exact end of a page, and the next page is not mapped, this will fault, because *dest will read 8 bytes, 4 bytes into the next page. So value is passed by reference, so the helper can be careful to use ppc_inst_read() on it. Signed-off-by: Michael Ellerman Reviewed-by: Jordan Niethe Link: https://lore.kernel.org/r/20200522133318.1681406-1-mpe@ellerman.id.au

powerpc: Add prefixed instructions to instruction data type

2020-05-18T14:10:39Z

For powerpc64, redefine the ppc_inst type so both word and prefixed instructions can be represented. On powerpc32 the type will remain the same. Update places which had assumed instructions to be 4 bytes long. Signed-off-by: Jordan Niethe Reviewed-by: Alistair Popple [mpe: Rework the get_user_inst() macros to be parameterised, and don't assign to the dest if an error occurred. Use CONFIG_PPC64 not __powerpc64__ in a few places. Address other comments from Christophe. Fix some sparse complaints.] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200506034050.24806-24-jniethe5@gmail.com